Revs fluctuating

[imported_andrewriding]

My A3 (T Sport) has started fluctuating on the rev counter. In a morning I start the engine and the revs hit about 1200rpm without touching the accelerator (I put this down to being cold so no worries). But...

Once the engine has been on for 10 mins or so the revs drop back to about 750rpm (this is where it is normally) but if you sit and watch the rev counter the revs will fluctuate (usual range is between 600 and 1000rpm) anywhere between 1400rpm and 500rpm (it really starts to struggle at 500rpm). This has been happening more often and will generally calm down by the time I finish my 45 minute drive to work - but will be noticable at every set of traffic lights along the way.

While it isn't a massive problem at the moment it is really annoying. Before i wheel it into the local dealer and part with all my cash, can anyone give me an idea of what could be going on with it. And more importantly does it sound expensive... /ubbthreads/images/graemlins/confused.gif

Thanks in advance

 

[mark69]

I have had very similar symptoms in the past that were traced (eventually!) to the throttle body. This was thoroughly cleaned at the stealers (twice) which temporarily rectified the problem only for it to gradually return although nowhere near as bad. Currently I am 'living with it' as AUDI are asking £280+
for a replacement......hope you get it sorted soon as I know what a pain in the **** it can be. Good luck , Mark C. /ubbthreads/images/graemlins/wink.gif

 

[rhubarb4]

I have this happening only on first start-up on cold mornings, they are like this OP has, I too have cleaned the throttle body but still have this problem, it seems to want to cut out and has on a few occasions has anyone else had this and found a cure as nothing has come up on Vagcom. Its on an S3 2001 AMK

 

[aragorn]

Talk about a necrobump!

I'd suggest it could be a vacuum leak.

 

[rhubarb4]

Talk about a necrobump!

I'd suggest it could be a vacuum leak.

Yeah I googled fluctuating revs and got this lol I will have a look at my lines as I did the N249 bypass before christmas so il check for any splits

Thanks, Chris

 

[A3 Oly]

this turned out to be a dirty tb for me. my symptoms were bouncy idle after dipping the clutch. very annoying and sometimes cut out.

 

[rhubarb4]

this turned out to be a dirty tb for me. my symptoms were bouncy idle after dipping the clutch. very annoying and sometimes cut out.

Sounds exactly the same I sprayed some throttle body cleaner in mine but didnt make much difference I feel your pain as it drives me nuts sometimes.

Cheers, Chris.

 

[A3 Oly]

take the tb off mate and give it a god clean with carb cleaner . ether get a new gasket or make sure you dont break the one on there. once done tho u will need vagcom to realign the tb. car feel much better once it has adapted.

 

[rhubarb4]

That will be beyond my talents lol and I dont have vagcom either so will be stuffed, guess il get a garage to do it chuffin cars should call them bottomless pits lol.

Cheers, Chris.

 

[A3 Oly]

tb is easy to take off and clean. where are u in midlands?