Sudden Loss of Power-Throttle Position Sensor?? Help!
#1
03-20-2009, 01:33 AM
Sudden Loss of Power-Throttle Position Sensor?? Help!
Hello I am new to this forum and not sure if this is in the right place, but I have a 99.5 A4 1.8t that I bought around 10,000 miles ago, it is chipped, KO4, and has exhaust if it makes any difference. This is long but any help would be GREATLY APPRECIATED!
The car has driven perfect ever since I bought it except for an occasional miss sometimes at full throttle, however I was driving down the highway recently and SUDDENLY it completly loses power for less than a second, jolts the car, flashs the CEL, and then returns to normal... CEL off, The problem seems to disappear but the next day the same thing happens, except this time it violently loses and regains power, constantly flashing the CEL every time the revs drop and it turns off when it returns to normal, a few times doing this it dies instead of returning to normal... not fun...at this point I decide it is time to bring it to a shop... on the way there, it continues to do this sporadically, seeming to happen more often as my drive continues, when I near my local mechanic it is barely drivable, even while pressing the gas steadily the car has a "mind of its own" and revs up and down between 500-4000 rpms randomly, finally it lurchs it into the shop parking lot.
I return the next day-my friends dad owns the shop- he unfortunately doesn't have VAG COM. However he scanned the code-not sure the #- and he says it came up as the throttle position sensor, although he says it could be the wiring as well- he will "try to figure out which"- 2 weeks later I get a call he says I can come pick it up- I come and all he did was change the spark plugs? He says they reset the computer and he took it for a test drive and it was fine. I pay for that and take it for a drive on which it seems to be running very nicely, until 10 miles later--- you guessed it--- same problem, blinks check engine, power drops, jolting violetly etc etc repeat. Today I bring it back and ask him to price out a Throttle Position Sensor, as he says he is almost sure this is the problem but didn't order it in the first place as it is a very expensive part and the car seemed fine after changing the plugs... however I'm not quite as convinced... I have been on these forums for days looking and have not come up with anyone having a faulty T.P.S. I was reading some other threads that seemed to have a similar problem and some possibilities were perhaps the MAF, Coil Packs, Boost/Vaccum leak, leak in air intake boot? I was thinking my self perhaps a clogged fuel filter or maybe dirty injectors, and I described it too a friend and he suggested the PCV valve?? If anyone has any diagnoses, thoughts, or advice that would be awesome... where should I start?? please help. Thanks in advance.
The car has driven perfect ever since I bought it except for an occasional miss sometimes at full throttle, however I was driving down the highway recently and SUDDENLY it completly loses power for less than a second, jolts the car, flashs the CEL, and then returns to normal... CEL off, The problem seems to disappear but the next day the same thing happens, except this time it violently loses and regains power, constantly flashing the CEL every time the revs drop and it turns off when it returns to normal, a few times doing this it dies instead of returning to normal... not fun...at this point I decide it is time to bring it to a shop... on the way there, it continues to do this sporadically, seeming to happen more often as my drive continues, when I near my local mechanic it is barely drivable, even while pressing the gas steadily the car has a "mind of its own" and revs up and down between 500-4000 rpms randomly, finally it lurchs it into the shop parking lot.
I return the next day-my friends dad owns the shop- he unfortunately doesn't have VAG COM. However he scanned the code-not sure the #- and he says it came up as the throttle position sensor, although he says it could be the wiring as well- he will "try to figure out which"- 2 weeks later I get a call he says I can come pick it up- I come and all he did was change the spark plugs? He says they reset the computer and he took it for a test drive and it was fine. I pay for that and take it for a drive on which it seems to be running very nicely, until 10 miles later--- you guessed it--- same problem, blinks check engine, power drops, jolting violetly etc etc repeat. Today I bring it back and ask him to price out a Throttle Position Sensor, as he says he is almost sure this is the problem but didn't order it in the first place as it is a very expensive part and the car seemed fine after changing the plugs... however I'm not quite as convinced... I have been on these forums for days looking and have not come up with anyone having a faulty T.P.S. I was reading some other threads that seemed to have a similar problem and some possibilities were perhaps the MAF, Coil Packs, Boost/Vaccum leak, leak in air intake boot? I was thinking my self perhaps a clogged fuel filter or maybe dirty injectors, and I described it too a friend and he suggested the PCV valve?? If anyone has any diagnoses, thoughts, or advice that would be awesome... where should I start?? please help. Thanks in advance.
#4
03-21-2009, 12:18 PM
Well if the codes pull up the throttle sensor then it is probably that. If it were the coils or MAF the codes would pull up MAF for sure, and the coils would pull up they are misfiring...I think. So I'm pretty sure it is what it says it is. On the other hand, it could be some wiring that connects to the throttle sensor...
Not for sure, but I know it wouldn't be the MAF or the coilpacks...so you can rule those out.
http://www.automedia.com/Throttle_Po...cr20040701ts/1
Read this for more information on the TPS. There are 3 pages.
Not for sure, but I know it wouldn't be the MAF or the coilpacks...so you can rule those out.
http://www.automedia.com/Throttle_Po...cr20040701ts/1
Read this for more information on the TPS. There are 3 pages.
Last edited by leo536; 03-21-2009 at 12:21 PM.
#5
03-21-2009, 09:55 PM
alright cool, thanks for the input thats good to know its probably not the MAF or coils. Ill try to check the wiring before I buy the part. and yes Crazyhawk good idea I just ordered the VAG COM cable off ebay. Im sure it will be well worth it as I dont plan on selling this car anytime soon.
#9
03-24-2009, 05:45 PM
Well from experience, usually bad coils would pull up misfiring codes. Also, a code for the MAF would pull up, but also if it was the MAF as soon as the car is turned on, it would immediately die. However they are all similar variations of the car responding inproperly. I would try this, try unplugging your battery, so pretty much reset the vehicles ecu and see if that does anything.
