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Throttle Body Cleaning

Symptoms:

Usually there should be no problems with the throttle body, so no symptoms. However, when I purchased this particular B5, it had problems keeping a stable idle (wide fluctuation), as well as odd behavior when releasing the accelerator during drives. The usual tune-up did nothing to alleviate the problem - spark plugs, fuel injector cleaning, air filter replacement, vacuum hose replacement, etc. Finally, during a round of carbon cleaning, I found the throttle body had accumulated quite a bit carbon, preventing the throttle plate from seating fully closed. The dealer the car had been serviced with was probably using some fairly terrible oil to cause such a buildup (after 30k miles at the time). As the car has now reached 60k miles, I was curious to see if there was still an accumulation in the throttle body - see for yourself. (illustration)

The most likely difference is the use of fully synthetic oils with an occasional engine flush added prior to draining old oil. I can only hope that this combination is also keeping the turbo's oil supply line in good shape - if I get around to pulling the supply line to finally just take a look at it, you'll find the update here.

Updates:

Oct. 2004 - The jury is still out on whether using a flush is a problem - the idea being that the thinned oil isn't capable of being a good fluid bearing for the turbo. I'm on the fence on this, as the turbo isn't in much use when the car is at idle. In the case of the '98, there was enough carbon around that there was justification for using a flush, but the current 2000 B5 has very little carbon build up. In this case, I haven't found a need for a flush - synthetic oil alone is very capable of keeping the oil pathways clean.

July 28, 2005 - Updated procedure to include DBW throttle bodies (pretty much the same procedure sans cruise control cable).

Part Information & Sources:

Note - always confirm part numbers by looking at the actual part mounted in the car! Mistakes will happen sometime, somewhere.

Part number:

1.8t throttle body gasket (all model years):    028 129 748

OEM Pricing: $2

Tools:

  • 5mm socketed hex (Allen) driver

Throttle body cleaning:

The throttle body is connected to the intake manifold, with the air intake hose from the intercooler connecting on the opposite side. (illustration)

  1. Start by unscrewing the air intake hose clamp. Pull the intake hose from the throttle body. (illustration)
    Note that the intake hose is thoughtfully marked with the correct mounting orientation.
  2. Pull the throttle position sensor connector from the throttle body. (illustration)
  3. On non-DBW (drive-by-wire) cars (with the AEB engine), the connecting rod on the throttle body allows the cruise control system to keep you comfy on the freeway. The easiest way to free the throttle body of the car is to pop the lower end of the connecting rod out of its bracket. (illustration)
  4. Using the 5mm hex driver, remove the four screws holding the throttle body to the intake manifold.
  5. You should now be able to pull the throttle body and gasket from the intake manifold.
  6. On non-DBW cars, remove the throttle cable by moving the cable through the maze on the throttle body. (illustration)
  7. With the throttle body removed from the car, take a look inside. There will probably be some carbon accumulation where the butterfly plate meets the throttle body walls - usually nothing substantial, but in my case there were solid chunks of carbon keeping the plate from closing fully. So much for wondering why ECU was going nuts with the idle.
  8. To clean off the throttle body, use some throttle body cleaner on cotton/paper towels to get rid of the accumulation. Try to avoid using a lot of throttle cleaner, and don't just spray a bunch into the throttle body - the throttle position sensor may be damaged (but shouldn't be if you're using actual throttle body cleaner. Take care if using carb cleaner you have laying around). Just take it easy with a little elbow grease and the throttle body will shine once again. Be sure to clean the edges of the butterfly plate, as well. (illustration)
  9. When you're done, remove the old gasket and clean off the mating surfaces of the throttle body and intake manifold.
  10. Reinstall in the reverse order, tightening the throttle body mounting bolts to 84 in-lbs / 10 Nm. Note - not 84 ft-lbs!

After the first throttle body cleaning at 30k miles, the idle immediately stabilized to the normal 800-850 rpm range and has stayed that way since. Lesson - use fully synthetic oil! If you notice any substantial carbon buildup in the throttle body (more than just a thin coating of carbon on the throttle body walls), you probably have carbon buildup on your valves and piston heads.

For the valves, toss in a bottle of Techron or BG 44K with the next tank of gas. For the piston heads, search around for information on combustion chamber cleaning. My piston heads had quite a bit of carbon build up at 30k miles, and after cleaning were pretty much spotless. Now at 60k miles, I've noticed some carbon accumulation again, so a combustion chamber cleaning write-up may be in the near future.

Good luck!

Comments:

  • I know this is an old post, but I wanted to post my success story. I have a 2000 Passat 1.8t with 225,000 miles on it. I have been driving around with the surging problem for about a year. I cam across this post and had my fiance clean the throttle body. It didnt look too bad, but it was just enough carbon built up that I guess that was the problem. After he put it back together there was no more surging. This really works...I would suggest everyone try this first before spending any money.
    Earline, Bridgeport, CT (USA) - Oct 17, 2013 @ 2:10 pm
  • Have a 1.8t with 70,000, cleaned throttle body, did not help much. still cel and emissions workshop light. would it be worth cleaning idle air control motor or valve that I believe is attached to body? I was told it needs to be preplaced. Please help
    Karen St. Louis MO USA - Aug 24, 2013 @ 9:29 am
  • have an a4 1.8t it is idling rough and missing it stated after the batter died and it sat for a few weeks any ideas
    michaelv - Jul 14, 2013 @ 11:04 pm
  • Just diagnosed my first VW T/B problem, it was bouncing away on idle on a relatively low milage engine - (points accurately to Kevin's Oil quality advice). Lots of sludgy oil in the air cleaner.
    But as a highly experienced Honda nut, I cant help but think... why is VW et al labouring away on an outmoded EGR system when the technology for a simple, effective one has been around for 25 years?
    It seems they have something to learn from the world's most prolific engine producer!
    Dave Hubbard England - Oct 8, 2012 @ 4:37 pm
  • These instructions and pictures were wonderful. I don't consider myself mechanical and this was super easy. Lots and lots of elbow grease but it's clean and back in.

    2001 Passat 1.8 Turbo

    Thank you so much!
    Laurel in Oregon USA - Sep 2, 2012 @ 8:59 am
  • My 2000 1.8 turbo PASSAT had the idle problem like everyone else on here. I took apart my throttle body and cleand it with gas. It would be recommended to use the carburetor cleaner. The gas works just as good. After cleaning the throttle body and clearly you can see the gas turn brown I put it back together witch is simple, when clean it should be bare mettle color not sluge or brown looking. the idle issue went away. This WORKS.
    Hawaiian boy - Feb 28, 2012 @ 8:28 pm
  • I had the same problem with my 2004 audi a4 1.8T(the engine stops when idle). it is over now after cleaning the TB that was full of carbon.
    Thanks for the hints.

    Machado
    Machado, from Mozambique(África ) - Jan 29, 2012 @ 4:18 am
  • I had the same problem(the enfune stops when idle). it over nos, after cleaning the TB that sãs fulo of carbon.
    Thanks for the hints.

    Machado
    Machado, from Mozambique(África ) - Jan 29, 2012 @ 2:51 am
  • Hi and like the others, thanks for your site and information.
    I have a 98 AEB and am about to give this procedure a go however neither this guide nor any of the comments below mention whether a TBA was ultimately necessary and if so how to do it. I have a VAG-COM, I just haven't used it much.
    David M, Australia - Nov 15, 2011 @ 10:08 pm
  • OUTSTANDING !!
    THX for Kev.UK easy disassamble (plastic to the TB) and WD40+Lint free wipes.
    Although the TB removal seemed a little complicated new gasket etc. The reassembly is a little tricky owing to the maze of pipes and being right up against the bulkhead. However, after a clean, with a small compact mirror the crud vanished and reassembly (trying not to pinch/squeeze the seal into the TB airflow) .
    I have put up with erractic idle and stalling at junctions for 2 years.
    This tutonic baby purrs like a cosy kitten !!
    For the the sake of 30mins <1g of carbon and a good nosey around the unseen parts of your passat. I Recommend.
    Top Man. 2 Thumbs up
    Chris. Poland - Nov 7, 2011 @ 1:52 pm
  • Just to say thanks. My 2000 1.8t sport estate K135,000 miles started hunting on tickover. Got worse over 4 months. Followed the advice, cleaned TB (it was coated in carbon). Switched on ignition with bonnet up and door open and left it to make noises for approx 1 min, switched off. Started engine and it went straight down to 850 ish on the rev counter and steady. Took it for a run and there is no lag, smooth from the bottom and runs likes a sewing machine. I am very grateful, it feels like a new car! Anyone can do it. Much obliged!
    Mike Elder UK - Oct 9, 2011 @ 8:49 am
  • Hi thought i would add that the carbon/oil is most likely coming from the crankcase breather or pcv system and you will also need to clean this too
    Nick - Sep 16, 2011 @ 5:56 pm
  • I have had idling issues on and off with my 99 passat 1.8t sport for the last 5 years now 62k miles and have changed the airflow sensor twice which almost solved the problem twice but today the car would not even keep running it just stalled and stalled, in desperation i googled the problem and found this advice, then all i did was remove the intercooler pipe from the throttle body and clean the throttle body and butterfly with dry shop towel and it now idles at a steady 800rpm thanks a million for this information
    Nick from England UK - Sep 3, 2011 @ 12:12 pm
  • My b5 Passat idles rough as well, i had codes pulled an had 300-304, (misfire) i cant seem to find a vacuum leak or anything. would it help to give this a try?
    Corey, Michigan - Jul 15, 2011 @ 9:04 pm
  • Had a little quality time with my 2001.5 passat this weekend. Dropped the AT pan, cleaned the sludge, replaced the filter and replaced the gasket. To add a little extra love, I pulled the TB and cleaned it. It really couldn't have been easier. Thanks for this site. It has been a huge help!!!!!!!!
    patrick - Jul 10, 2011 @ 11:32 am
  • my golf idles to hi when i starts it every time
    jaco sa - Jun 5, 2011 @ 10:47 am
  • Just a note of thanks for the site and great info on it! I've got a 98 Passat I'm trying to keep running; not that many extra funds for a car payment kicking around with two kids and a mortgage. There's such a wealth of useless, incorrect knowledge out there but yours was always dead on.

    Thanks again!
    Paul
    Paul - Canada - May 19, 2011 @ 5:32 am
  • thanks for the advice man worked a treat and its so simple to do
    very helpful indeed
    thanks man
    andy oakley uk london - Apr 25, 2011 @ 9:25 am
  • awesome write up - I had the same type issues, sputtering and rough idle. I followed your article and great photos, all cleaned up and shiny and running MUCH better!
    Cheer!
    tedd - Feb 8, 2011 @ 12:29 pm
  • I'm the 3rd owner of a 2000 Passat Wagon that I bought in 9/2009. The car has had a slight idle with a hesitation on throttle since we bought it. I figured it was probably something serious since it's approaching 100,000 miles! I WAS WRONG. I cleaned the throttle body by following these instructions and the car is LIKE NEW! THANKS!
    Adam Merkley - Jan 20, 2011 @ 5:53 pm
  • Holy crap, I've had a rough and erratic idle on my 98 A4 1.8T for over 3years! And cleaning the throttle body did the job and fixed it. So many dealerships and mechanics tried to solve this issue, yet not one person said to clean the TB. Thank you, thank you, thank you! keep this site going so that others can benefit!
    DC - Jan 17, 2011 @ 8:37 pm
  • Thanks for the writeup guys. With your help, I have successfully removed, cleaned and reinstalled my throttle body. Having lived with the pulsating idle (4-500rpm) for the last 18 months and convincing myself it would cost a fortune to fix, I ignored it until recently. When I googled Audi A6 throttle body cleaning, I found this site. My throttle body was incredibly dirty with disturbing accumulation of crud in the throttle gallery but using carb cleaner and a couple of wood coffee stirrers, it cleaned up sweet. Car now running at 800rpm and idles like a swiss watch. thank you.
    Kevin C, Ireland. Audi A6, 2.4 V6 - Nov 2, 2010 @ 3:57 pm
  • We had a 99 passat wouldn\'t idle was always stalling. Took the TB off and cleaned the gunk out of it and wow to my amazement it worked like a charm. I cleaned it with brake cleaner. I think there\'s a sensor on the side thats connected to the valve so when it shuts it hits the sensor for idling. If there\'s just a little bit of build up it\'s enough not for it to close all the way.
    Ronald - Aug 3, 2010 @ 6:00 pm
  • I was told by that my electical part of the throttle body on 99 passat was bad,I found this unlikely has anyone else had this problem
    Tammie U S - May 7, 2010 @ 1:11 pm
  • Wow. I have a 2001.5 passat. Idle would drop if i applied a little gas to it and took my foot off. Did these steps, took 15 minutes and my car runs better then when I bought it at 30k miles. (Now has 114k) Great writeup, I saved 500 bucks and you deserve the $492.00 cuz i spent 8 bucks for the material to clean it :p
    Jason, USA - Apr 15, 2010 @ 10:28 pm
  • Thanks! Great post! bought 1.8T about a month ago and nearly stalled EVERY time i depressed the clutch. Started up the stalled immediately without touching anything :S Took off and cleaned throttle body with break/ clutch cleaner and got carbon deposites off and problem solved :D took 20 mins and well worth a try!!!!!!!!
    Tom uk - Apr 5, 2010 @ 11:13 am
  • Just fixed my idle problem of 6 months! Took about 10 min\'s. Didn\'t remove throttle body, just removed inlet hose, sprayed with WD40 and cleaned with kitchen towel (paying particular attention to mating faces between butterfly and body)..... Great post.
    Kev United Kingdom - Apr 5, 2010 @ 7:44 am
  • Great post. Thanks a million. After 8 months of changing every sensor and hose... i found this and my RPM needle found peace.
    zlaki - Jan 27, 2010 @ 8:10 pm
  • What a nice piece of information. Save me lots of $ on the almost 100k km 1.8T. Thanks.
    Joe (Hong Kong) - Jan 12, 2010 @ 9:42 am
  • WOW!! This is the best Christmas present I could get. My 2001 Jetta was idleing up and down. After cleaning the TB it is running so smooth. I just spend $300 to tune and replace some overpriced hoses that had no effect on the idle. Wish I had seen this post sooner
    Thank you
    Mike Thornton Virginia,USA - Dec 16, 2009 @ 9:35 pm
  • EXCELLENT. I thought I had serious issues when I purchased my 2001 (2001.5) VW Passat. The previous owner told me he replaced all of the coil packs and spark plugs but still could not get it to idle correctly. I popped the Throttle body off this afternoon, which was really easy to get to, and there was all kinds of nasty in there. Car had 107k on it. It took some heavy duty degreaser and scotch brite pads but i eventually got it all. I also disassembled the butterfly so i could have easier access. Threw it back in and presto. The car runs perfectly now. THANKS so much for the guide and advice. Saved me a lot of money.
    Austin H, USA - Nov 19, 2009 @ 3:46 pm
  • Another success story thanks to all of you. our 98 Passat would die at most stop signs. after cleaning the TB it started right up with a nice even idle. drives like new!!!!
    thanks!
    Peg B - Nov 8, 2009 @ 1:55 pm
  • problem, helpful
    kareem - Aug 7, 2009 @ 11:06 am
  • (Correction!) the car won\'t start EASILY when warm
    kareem canada - Jul 21, 2009 @ 10:47 pm
  • Hi there! I have had a problem regarding the idle speed which was high to 1200 and more a bit sometimes, in addition to that, the car won\'t start when warm, and the epc was all time there and engine workshop aswell, so, i did researches and broke my mind aswell as i aked Allah for help, so i found out it was the crankshaft position sensor, which vw dealers call it impulse sender, the color of its head connector is grey, it comes right underneath the engine coolant tank(g12) and it goes to battery direction then turns towards the front of the car making ninty degres then dips inside downward to the groundfloor direction and comes out behind the engine oil filter and there where it is plugged, and has one screw, it has a circular end, so as soon as i replaced it with a new one, all problem of engine workshop was gone epc and idle speed, and much more and better performance, i have found the proble of emissions workshop when it pops up with the engine light check, it is because of catalyst converter or the sensors of it, so if ever you have had a misfier for longer then 3 minutes then it is the catalyst, if not at all, and you know the history of your car then it is just one or more of the oxygen sensors.
    May Allah(only one true god worthy of worship) help us to be help full to one another. ameen.
    kareem canada - Jul 21, 2009 @ 10:36 pm
  • mannnnnnnnnn!!!!!!!!!!!!!!!!!!! This stuff is the best.had idling,stalling and jerks in between
    acceleration problems but after i cleaned out the the throttle body like u suggested, it`s all gone like magic.strongly recommend to everyone.however,don`t forget to leave hood and driver side door open for 3 mins before starting vehicle after cleaning.Also ,cover sensor /electrical area with some kind of tape to prevent getting contact with spray.
    Eric T ,US - Jun 19, 2009 @ 4:23 pm
  • had same probs with stalling , thought it was serious problem , cleaned throttle body as instructed and thank you so much , my car drives like a dream , it could,nt have been easier to fix

    andrew , uk - Mar 29, 2009 @ 1:57 pm
  • Awesome write-up! Sincerely appreciate it, especially since the Haynes manual has horrible pics. Just cleaned the TB on my \'04 1.8T and rough idle improved tremendously (smoother ride, too).

    Tip (which should be obvious, but I was hungover): remove bottoms screws first. Holding up the TB while dealing with the intake hose during unscrewing was irritating enough that I had to insert a top screw again.

    Oh, and I hope dude below me found what he was looking for - if not, try http://www.passatworld.com/forums/
    Scott - Texas - Jan 4, 2009 @ 1:17 pm
  • I have a 98 b5 passat manual 1.8 turbo. Am getting a Check Engine Light after taking it to the dealer for a non related issue, and the code is P1565 \"idle speed control throttle position lower limit not obtained\". Dealer says the throttle magically went bad while it was there (wasn\'t getting this light before) and I need a new throttle body/sensor for some outrageous price. I cleaned the throttle body, which wasnt\' dirty, and still got the CEL. I then replaced my TB/sensor with a used one I got on Ebay, and get the same CEL and code. Can anyone tell me more about the throttle body adjustment, or this method of leaving the door open/hood open, etc? The car runs smooth as silk, I think this is a code reset problem of some sort. Would really like to get rid of this CEL. Thanks!
    - Oct 27, 2008 @ 12:28 pm
  • Was happy to try this on my 97 Audi A4 1.6. Had the fluctuating idle problem for years. I couldn\'t get the TB off, probably wrong tools (wrong person!) so ended up just cleaning what I could though the end whilst holding the butterfly open. Plenty black crud in there. Anyway put it all back together and idle is 100% better, maybe the very slightest wobble looking at the needle on the rev counter, but not noticeable really. Turned the ignition on and waited about 40 seconds before starting, don\'t seem to have any issue. Thanks for the tip.
    Dan UK - Oct 11, 2008 @ 5:16 am
  • I am not mechanical at all - recently my car isn\'ty starting well. 2001 Passat 1.6 petrol manual - Problem started this weekend. When I turn the ignition the starting motor kicks in but feels like fuel isn\'t getting to the engin. I assumed it could be the auto choke or something.. but now thinking it mighjt be related to Throttle Body - after a few minutes I try start engin again and will slowly kick in - feels like te car is about to cut out but if i tease the accelerator, i can get it starting- seems to run fine then until I pull in and switch off again. I also have symptoms of the revs dropping on the car when idle (at lights etc) not so bad as to nearly cut out, but definitly noticable.
    Any advice - I really am lost and don\'t want to go to a mechanic who would rip me off.
    Thanks,
    Brendan
    Brendan H - Sep 29, 2008 @ 5:01 am
  • I am not mechanical at all - recently my car isn\'ty starting well. Problem started this weekend. When I turn the ignition the starting motor kicks in but feels like fuel isn\'t getting to the engin. I assumed it could be the auto choke or something.. but now thinking it mighjt be related to Throttle Body - after a few minutes I try start engin again and will slowly kick in - feels like te car is about to cut out but if i tease the accelerator, i can get it starting- seems to run fine then until I pull in and switch off again. I also have symptoms of the revs dropping on the car when idle (at lights etc) not so bad as to nearly cut out, but definitly noticable.
    Any advice - I really am lost and don\'t want to go to a mechanic who would rip me off.
    Thanks,
    Brendan
    Brendan H - Sep 29, 2008 @ 4:46 am
  • I guess this is 4 years since last post.

    Just wanted to say how great this write up is, will do it next weekend. For some people that the problem still persists after cleaning the throttle try:

    spark plugs

    fuel filter: on the right side of car at the rear, follow the break and fuel lines until you get to a bit thats covered with a plastic cover, remove the 2 bolts and bend open to reveal filter

    MAF (mass airflow sensor) its connected between the air intake on engine and air filter has wire connected.

    Not sure if this write up applies to my car.

    V5 2004 passat SE
    carbon12 Australia - Aug 30, 2008 @ 4:52 am
  • I used to have a passat 1.8t which stalled when i put the clutch down. VW wanted £260 to change MAF and lambda sensors. I cleaned the throttle body without removing from the car as per instructions, and it\'s fixed. MPG much improved and stalling gone!
    Mat Bailey, UK - Jan 23, 2008 @ 12:52 pm
  • Is the throttle body gasket on a 1999 Passat V6 different?

    I\'ve seen it listed - from $34 to $28.
    Louis Rodriguez - Oct 31, 2007 @ 2:56 pm
  • Update from my previous posting.
    Car: 2002 1.8T PASSAT with 54k
    1) Did cleaning on the throttle body
    2) Started the engine, got real rough idling and misfire
    3) CEL shown up
    4) Left the front driver side door and hood open for 3 minutes
    5) Car learned the new throttle position or what ever it is
    6) Now car runs smooth, but CEL is on. Seems like it is some stored data.

    I hope the step 4 will be useful. If you touch throttle body, do the step4 before starting the engine
    San, TX, USA - Oct 23, 2007 @ 10:07 pm
  • I did it just now. But for some reason CEL shown up and engine started misfiring Car is kind of in a not drivable condition. Dont know what went wrong. I guess the cleaner went and hit some sensor.
    San, TX, USA - Oct 23, 2007 @ 8:20 pm
  • Hey thanx a lot, idling went away but an engine light came on with an ETC light. I sprayed a lil throttle body spray in the intake manifold, i think i\'ve mida sprayed a sensor. Now it seems like it wants to turn off when I put it in park. Do u think its that lil sensor on the intake manifold close to the throttle body?
    Alan Castillo - Oct 23, 2007 @ 6:28 pm
  • hello, my 1.8T AWD has a P1556 code said my charge control goes negetive, and i jus wondering if cleaning of TB and MAF would help?
    thx
    Dave Canada - Sep 22, 2007 @ 1:43 am
  • I have a friend that cries because his 1999 Jetta does not hold at idle. The car starts , becomes erratic and finally stalls. Do you think is the TB the problem?
    I also figure out that this part is not as susceptible to mechanically or electrically fail. I \'ll try this cleaning procedure and hopefully my friend will be surprised. I \'ll let you Know guys about the results. I have a 2000 passat, !.8T and I love it.
    Tony Figueroa - Sep 10, 2007 @ 5:00 pm
  • Many thanks. I had the same idling problem. I cleaned the throttle body for my 2000 passat 1.8t, after reading about this. Man this shit worked! B4 I tried the dealer, they told me to buy the whole throttle body for $470. I did a little research and read about these great instructions.
    Wongsonadi, S - Aug 15, 2007 @ 7:25 pm
  • Is a TBA really needed after a throttle body cleaning?
    I own a 99 Passat 1.8T(APU)
    Han v V (Netherlands) - Aug 3, 2007 @ 8:08 am
  • well on the wifes 2e passat 2.0ltr 8v has a big stalling problem, its been like this for almost a yr, now mot due tis time to sort.
    cleaned the tb, well was very very little coke, so went ahead and cleaned it, after reading this thread, still the car holds no idle, its been like this for a while, using my vag com scanner, ecm shows no errors,
    changed all sensors etc over time due to failures, still the stalling problem remains.it can only be tb, when i hold accellerator down by a few mm, perfect idle at 1000rpm. its a real pain, i have noticed that vag sensors seem to be very poor for long term service, other makes of sensors seem to last many times longer.

    pretty much given up,got to be faulty TB...typical VW....very wa**..

    seen this problem on far tomany vw\'s from 1991>1996
    jon united kingdom - Jul 30, 2007 @ 7:03 am
  • Thanks for the great write-up! My \'99 AEB had a wildly fluctuating idle. Cost me all of $6 (gasket and cleaner) and now my idle is ROCK SOLID! The only thing I did different was that I sprayed more cleaner than you suggested. Since my car is not DBW I figured it was OK (and it was).
    Peace - USA - Jul 28, 2007 @ 11:46 am (website)
  • Thank you for my new car. I have experienced the idle flux for approximately 2 years. Recently, I have had a stalling problem at stop lights and stop signs. I followed the directions and illustrations in hope to remedy the situation. The carbon build up in my 99 Passat\'s (140K) throttle body was extensive. After spending $2.75 on a new gasket and $3.99 on a can of cleaner, my car runs like new. Thank you for the detailed info and solution. I saved $450.00 that I was quoted by the dealer.
    Jeffrey K. Evans - Jul 3, 2007 @ 8:58 am
  • After spending about $3,000 or more. my 1998 audi a6 is not running.when the car idles at
    about 1200 rpm,the idles bounce up an down.i did new timing/water pump/belt tensioner/
    and all new pulleys/all the oxigent sensors/maf sensor/ 2 .new catyl converter & gas filter.and plus \"i\'ll be lucky to get 30 mph\".could this be a THROTTLE BODY problem?
    has no balls(no power)
    CLYDE (in hartford ct) - Jun 19, 2007 @ 10:27 pm
  • Thanks for the directions! My 2002 Jetta 1.8T (mileage = 105,000) was displaying the typical symptoms (rough start, rough idle, cranky at low speed). I followed your instructions (for the most part) and it\'s running like new! It hasn\'t run as smoothly as it just did for about 30K miles.
    ThePaulson - Detroit, USA - Jun 16, 2007 @ 6:21 pm
  • Absolutely brilliant - just done my 99 Passat 1.8T(APU) and it\'s transformed the car. It\'s done 110,000 miles and had a real problem with a surging idle. Was almost impossible to drive very slowly, like round a car park . . . Half an hour later and bingo - problem solved and a better drive all round. Thank you so much for the clear concise instructions.
    John, Devon UK - Jun 14, 2007 @ 9:22 am
  • 99 PASSAT 1.8t Turbo Here 129k
    I,ve been experiencing the RPM Flux at Idle for about 2 weeks now. Yesterday I took it to the Dealer (Argh!) for some Recall work and asked to have the idle problem troubleshot. Well they called me for a $750.00 Mass Airflow Sensor replacement and Throttle body cleaning. I told them no..Thank God! I read these instructions, popped over to the local auto parts store, purchased throttle body cleaner and Whammo! Car runs like new again. It was a breeze to remove the body assy. THANKS SOOOO MUCH for your help on this. TechTip- use a small bristle brush soaked in TB cleaner to enhance the cleaning of the body valve and walls. I even pulled my ABS control module out to send in for rebuild. ($130.00)
    Trent, Oregon, USA - Apr 25, 2007 @ 9:21 am
  • A mechanic told me that cleaning TB is only half the solution as he\'d still have to \"reset the computer\"???? Is that correct--or is he just feeding me a line?
    James T., USA - Mar 31, 2007 @ 2:44 pm
  • Great illustrations and clearly written - you\'ve saved me a fortune, on my A6 1.8T issue had all the usual suspects checked / changed, inc. Air mass meter,(which improved but didn\'t completely fix) then the diverter valve, tried redex and nothing cleared it. Spent a couple of house following your diagram, and one carb of carefully applied carb cleaner - and hey presto, car now drives like a dream, not an idle problem in sight!! Cheers.
    Stuart *(Audi A6) - Mar 29, 2007 @ 5:13 pm (website)
  • I just started to get this problem after the crazy freeze in Texas in Jan \'07. I looked inside and mine was just filled with crap. It seems like the bolts were originally installed too tight because they were quite a pain to remove. The old gasket had become one with the car, so I installed the new one over it. This may be famous last words--we\'ll see.

    My road test after the installation shows no more idle problem. The only tip I may add is I sprayed the snot out of mine far away from the car, but then dried it off by leaving it out with the throttle stuck open with a plastic handle I had laying around.
    Adam Preble - Jan 20, 2007 @ 12:41 pm (website)
  • Great write up my man. It\'s a pity I only found this website now. Had swapped out air filter spark plugs and ignition coils but had no joy. Brought to mechanics and he cleaned TB. Runs perfect now. Please feel free to add more TS tips to this web site.
    I have a question for you.
    Is the rear cam tensioner seal easily changed. I have an oil leak here?
    Froggyboy - Dec 6, 2006 @ 9:28 am
  • Thanks for the great writeup and instructions! Did my 02 gls 1.8t today and it was super easy. Got good results. TB had moderate build-up at 57k miles. Thanks again !
    Doug - dreyn1957 - Nov 29, 2006 @ 12:49 pm
  • Thanks so much for a very clear write-up. I finally managed to do mine, and it was pretty easy thanks to the images. Also, I have a B5.5 and I did not have to go through the step of removing the rod, as it is not there. So for me it was even better.

    I did find a lot of carbon buildup on the body, so it was nice to clean it all up. Initial startup of the engine does show less fluctuation, but I need to take \"The Professor\" out for a drive.

    A tip. You can use a cotton bud to get to the tough places.

    Thanks for your help
    Harry
    Harry - USA - Sep 17, 2006 @ 5:16 pm
  • Great write up...saved me the $160 that VW wanted to charge me. It took me thirty minutes to make my car run like new again. Thanks!
    Jeff (Atlanta, GA) - Aug 28, 2006 @ 1:15 pm
  • Doh! I just had a new one put on for about six hundred bucks because she couldn\'t hold an idle. I wish I\'d read this first : (
    Helga - Texas - Aug 19, 2006 @ 1:44 pm (website)
  • 98 Passat 95k miles, my wife was irate becase of the stalling and irrational idling of the car. I almost had to trade her in (the car that is). Thanks for the tip. After trying a tune up(including new plugs and stuff), injector cleaners, high rpm driving, etc. I followed your instructions and the car runs like new again. It\'s amazing how a little carbon can screw up the car so bad. After cleaning the components I notice that they are all machined to high tols. which indicates to me that even the slighetest amount of carbon build up will impede performance.

    Thanks again!

    BTW I called the dealer about the problem and they said that they replace alot of throttle bodies. I guess they\'re not in the cleaning business.

    OUT.
    Chris Pfahl (Ohio) - Jul 29, 2006 @ 9:46 pm
  • Great Writeup..
    2002 1.8t passat here. Was easy and worked like a charm
    Aagiants - Jul 1, 2006 @ 11:33 am
  • When my idle started behaving erratically, my mechanic told me I needed a new throttle body. Did a little research on the net, found this page, cleaned by TB per your instructions, and like the guy above said, it\'s like driving a new car. And it didn\'t have much carbon in it at all -- I guess all it takes is a small accumulation in the right place to mess up the sensor. You just saved me hundreds of dollars. Gotta find a new mechanic now.

    Brian (USA) - Jun 21, 2006 @ 7:32 pm
  • Great write up. After 45 minutes of work and carefull cleaning my idle problem is gone for good. Thanks now on to the Timing belt.
    CJ, USA - Feb 27, 2006 @ 9:35 am
  • Hi, I\'ve got problem with TB plus the EPC and CHECKENGINE lights up with TPS malfunction info. Brand new TB is around $440. Is anybody know any aftermarket place I cloud get TB (TPS)? Please help!!!
    GoLiath - Feb 20, 2006 @ 9:45 am
  • Great write up. I just did my 1st cleaning at 92k miles. Since I have been using fully synthetic motor oil ever since I decide to change my own oil, my TB only has a very thin layer of carbon build up near the valves.

    Just like to add something to your write up. I have a non-DBW car. I found it almost impossible to remove the connecting rod they way you did on step 3. So I studied the ball joint located at the upper section of the rod. Found that by removing that thin wire that prevented the ball from coming out, the joint will easily pop out with a gentle help of the flat head screw driver. This makes the cleaning and install so much easier.
    Jia Li, USA - Oct 29, 2005 @ 1:46 pm
  • Thank you! I\'d had the same idling problem (occasionally almost stalling) for months and was worried it was something more serious. I followed your instructions and the problem is completely gone. My Passat drives like new!
    Chuck, USA - Jun 22, 2005 @ 4:38 pm
  • I am going to try it this weekend thanks alot for the tip
    John Healy - Apr 21, 2005 @ 7:23 am
  • Great instructions!
    Additional tips:
    1. Cover the intake sensor with something to prevent damage that may be cause cleaning agent. Wrap a thin cloth around sensor, then overlap with plastic wrap, then enclose with duct tape; this almost assures non-exposure.
    Spray away!!!
    2. Removing and reinstalling three of the four mounting nuts can be a real beeoocchh (pardon my English). Use of a little mirror can save a huge amount of time.
    Sam Crawford - Sep 10, 2004 @ 1:13 pm
  • Is the ATW the 152 tooth Timing Belt? How do I know which motor I have?
    Joe M - Aug 6, 2004 @ 9:15 am
  • I\'ve removed my TB when replacing the vacuum lines on my ATW. There was a this film on the bottom of it, but no chanks. Didn\'t have any carb cleaner and since this is DBW and I don\'t have a VAG-COM to do a TBA, I just didn\'t mess with it. Has always been idling perfect at ~800 RPM. So I guess a little film is fine, as long as it doesn\'t interfere with the operation of the butterfly valve.
    MasTRE - Jul 26, 2004 @ 1:40 am

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