vw passat 2.0tfsi - Urgent help needed - car revs are random!!!

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Wed 9 Nov 2011 23:40
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - Med

hey everyone, on my way out to my gf's, about 2 mins from her house the car revs started going up & down on its own, i didn't take much notice at first until i got eround the corner - the revs started going up higher and higher, started to get really worried i turned the engine off.

I tried again, turned the engine on and it was going up and down - then again, started going up by its self.

I've tried disconnecting the battery, i.e. partially resetting the ecu but with no joy.

I am really worried to drive the car to work tomorrow so any of you late sleepers who can reply i would really appreciate any help.

Many thanks.

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Wed 9 Nov 2011 23:51
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - rtj70

Sounds a lot like a scenario on here before from someone driving a Mazda diesel.... oh hang on that was you?

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Thu 10 Nov 2011 00:14
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - Med

yes that was me, I just dont have alot of luck with cars. This car I bought used about 2 months ago, since then ive always used the best fuel and oil and have had the car fully serviced... the car is not over running but when idle this is when it happens up and down up and down and randomly goes up slowly.

I really need your guys help..

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Wed 9 Nov 2011 23:52
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - bathtub tom

Have you looked at your sump oil level?

AGAIN!

Damnit, RTJ70 beat me to it.

Edited by bathtub tom on 09/11/2011 at 23:53

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Thu 10 Nov 2011 00:10
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - Med

it was high but i believe this is because the engine is warm. I will check it in the morning. Drove to france on the weekend and did around 800 miles. Had loss of power twice, no warning lights, could this relate. Just to make sure you know this is the petrol version not desiel.

Thank you for you quick reply

what else can i check

thank you again

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Thu 10 Nov 2011 10:23
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - injection doc

hi Med

what makes a car idle erratic like that is an air leak or throttle body issue.

I would suggest checking all the hoses, but there is an obscure breater hose that splits longways just above the gearbox and you can only really see it leaking with a smoke pro test. The leak could be tiny ! unlikley that you would hear it iether. Do not use WD40 to try and find it as the silicon damages the hego sensors !

2nd i would wash out the throttle body, if its dirty sometimes it stops the flap completely shutting which confuses the throttle posistion switch and the car doesnt know its back at idle mode and it make it rev all over the place.

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Sat 12 Nov 2011 14:06
vw passat 2.0tfsi - Urgent help needed - car revs are random!!! - Med

Hi Injectiondoc, thank you as always for your valued comments.

These are the fault codes:

P0234 - Turbo Overboost condition. Upper limit exceeded - intermittent

P1317 - No Info

P0642 - Sensor reference voltage "A" circuit low - signal too small intermittent

P1093 - Bank 1 fuel measure system 2 malfunction - signal not plausbile intermittent

P1602 - Voltage supply low (30) signal too small - intermittent

P0507 - Idle air control system RPM Higher than expected - upper limit exceeded intermittent.

The thing is, these codes may have been on for a while, whether they relate or not i don't know - it seems more like the last code but the garage has failed to see what that could be.

I passed on what you said about the throttle body, they checked and said its fine, they spent hours checking all hoses etc but cant find anything. Whether its just me or not but i feel that the cars pulls a lot quicker than before, ah another important thing that i have noticed is that when i turn the engine off there is a noise just before the engine cuts out, it sounds like a chuggeling noise (i hope that word makes sense, never used it before) or a noise that sounds like the engine has come loose from a mount or something, only lasts about 2 seconds when turning the engine off.

What do you think!? Oh and yeah, it was me with the Mazda which is why this scared the crap out of me when it happened, it only wernt to 2,000rpm then came back down, this is the reason why i bought a petrol car......everyone is telling me i should be riding a bike instead of driving a car - i do have extremely bad luck with them. :(

Thanks

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