Rama

I have a 99 A4 2.8 Quattro with tip. I notice that the car idles much smoother in neutral than in drive. Idle characteristic in 'drive' is actually quite rough (engine hum can be heard, vibration felt in steering wheel). Shift to 'Neutral' and everything seems OK. RPMs in both cases fluctuate between 700 and 800. Any ideas on whether this is normal? I have read something about an 'idle stabilizer valve'; could this be the culprit?

ChuckH

...when in drive are still trying to pull the car to some extent, even though the brake is on, I think. You also have all the driveline hooked up, wheras in neutral, the engine is spinning all by itself. This is normal.<p>A bad idle stabilizer valve will cause the revs to drop and rise significantly. Your RPM's might dive to 300 RPM's, (or even stall the engine), and then jump up to 1200 RPM's, etc. <p>Charles<br>

Chris K

Although based on my experience, my car smoothed out quite alot after about 2000 miles..

Rama

My concern is the engine hum/buzz and vibration in the steering wheel. Quite annoying...is this typical for all 2.8/Tip cars out there?

Henri Berger

Yes, mine buzzes too, although less than when new

ED

1

ChuckH

Agreed! It does seem to lessen as the miles pass! :-)

ChuckH

Will probably lessen over time, but I think everybody has this.

Rama

Unfortunately, mine seems to have gotten _worse_ over the past 5 months since I bought the car! Have about 5000 miles on it, mostly close to home (home == Bay Area). Maybe the morning commute is rough on it (grasping at straws...).