Hi, i have a 2004 Audi A4 3.0L Quattro Avant. I noticed something weird recently when i drive the car steadily around 2000 rpms, the rpm/engine will frequently go up and down between 1800 and 2000. RRRrrrRRRrrrRRRrrrRRRrrr, until i get out of the 2000 rpm range.

Anyone know what's causing that and how to fix it, or if it's any cause for great concern?

Thanks.

 

My '05 3.0 was doing something like that. In my case the crankcase pressure control valve was bad. Easy to replace, no screws even, just clipped in place next to the throttle body. I also had a couple of broken vacuum hoses, which might have contributed.