I first noticed this right after I got my 3.73 gears installed, whether it has to do with them or not, I am not sure.


When I am at idle, sometimes the rpms will just jump from 600 to 1000 or 1200... and then go right back down.. or keep bouncing up and down.

I am not touching the gas at all...

I have an A4, and I am really confused as to why it is doing this. It doesnt do it all the time, just sometimes. Usually when I have been running the car for a while. Does anyone know whats up?

 

Maybe a vacuum leak. It would be good info to know what your IAC counts are and if possible, some data logs.

 

Where can I get these tested at? or how can I find these out?

 

A scan tool will tell you the IAC counts. Some scan tools can data log, but the best way is with a laptop and cable connected to the DLC on the car. You can go for a drive and capture the log of what the computers sees and what it is doing. Without some sort of diagnostic tool support, you can only guess at what is happening or what might be the cause.

Do easy stuff first, like checking all vacuum lines and connections.

 

Will do, thx for the replies.