constant small Fluctuation in revs

[Rolling Thunder]

When warm (never when cold) the rev counter shows a fluctuation of about 100 revs about once every 2 seconds when driving betweeen 1000 and 2000 revs.

It doesnt do this when idling but you can just about feel it when driving - its like the car having a pulse. There are no warning lights and no other symptoms. My 2002 A4 has only done 21k from new so it *might* be an early sign of a multitronic issue i guess

I have the car booked into Audi on Monday for a health check anyway - but just wondered whaat it might be before they say something expensive

 

[Mike B]

Which engine?

 

[Rolling Thunder]

ah yes sorry its a 3.0ltr...

 

[Pabs]

my 1.8t has started to do this but at idle, i think the MAF is on its way out, could try unplugging it with the engine running see if it still does it,

21k on a 02 plate that is hardly broken in, good find how long have you had it

 

[xpanse0]

Hi

How did you get on with this problem with your audi dealer. I am very concerned because i have just bought same car with same problem !!!!!!!!!!!

Hopefully it wasn't you i bought it from?

Best
S

 

[marktdisport]

have you tryed some injector cleaner !!!! this may help if your injectors are dirty and if you use non addative supermarket fuels.....

 

[beachbuggy]

There's quite a few write ups on the s3 forum about the same thing, a throttle body clean and a reset/adaptation of the throttle body will solve your problem. Seems typical of VAG throttle bodies.

 

[marktdisport]

a also done a throttle body clean to my cupra aswell with injector cleaner

 

[Rolling Thunder]

Just back from the Audi healthcheck. No issues other than a twisted dipstick and an observation that as the car is 9 years old the gearbox oil should be changed (even though its only done 21,000 miles). So I have booked this in as a damage preventative measure. Comments on the idle fluctuation were not conclusive as they pointed out the spark plugs and fuel filter had not been changed before either. So I will replace them as a matter of course and then see where we are....

 

[xpanse0]

Hello again. Just had diagnostic on my Audi a4 auto. They think it could be gearbox related. Damn. Regarding rev fluctuations. Have been told by another that the clutch plates need replacing. Would love to know if any who has had this problem has managed to cure it. I have read that someone else had this problem and it was the torque converter, however, there is not one of these on my CVT gearbox. Any news yet ?

 

[Rolling Thunder]

Audi have checked my car out (and found no issues) but helpfully said the throttle body probably needs a clean / adaptation of the throttle body...

 

[xpanse0]

Let me know how you get on with the throttle body. I am going to try cleaning the front wheel sensors before I give up and pay for the 7 plate clutch upgrade . GULP. It better work.

 

[Wussell]

Interesting about the fluctuating revs. Have the same problem and am currently trying the injector cleaner stuff (Redex) and Optimax fuel. Anyone have any tips on the throttle body cleaning? i.e. how tricky is it to do?