I have an Audi 2.8L with a problem nobody could fix i took it to 3 diffrent machanics none of them no wats the matter wit it. Frist problem when in park the RPM needle doesnt stay steady at 1k it bounces up and down. 2nd Problem when decelerating from 60mph the needle drops in 200rpm at a time. Last problem the car will vibrate after it downshifts to acelerate.

I need Help bad i spent 2k alrdy i got no idea what to do

 

1. The 12v idles like a weedwhacker compared to other engines, so i'm gonna assume thats your motor. Unless its jumping around by hundreds of RPMS, don't worry about it.
2. The tach is marked every couple hundred RPMs, a drop like that when decelerating doesn't sound like a problem to me?
3. What kind of vibration? Can you feel it in the steering wheel or the pedals or what?

Also, a little more info about the car would def. help

 

You should have your car scanned for faults codes and post the codes here. AutoZone and Advance (at least) will do it for free.

 

Search the forum for "seafoam" and do a thorough seafoam treatment - all three treatments (fuel, oil, and vacuum). It sounds like you could have a vacuum passage or the IACV clogged or carboned up, or maybe some other related crap. In any event, seafoam is a good treatment to do, it may well help alleviate one or more issues, and if it doesn't fix your current problems, it'll still benefit your engine.

Take a look at your plugs too though and make sure they're not in bad shape, and that the valve cover gaskets aren't leaking oil down onto them.

 

I think there was a TSB on this condition, it had to do with what I call the rats' nest... a bunch of vacuum lines that all come together in a single point source by the manifold. All the symptoms have a vague similarity in the engine loading characteristics... Tweaked, you know what I am talking about?

OP, get a can of carb cleaner and spray around the engine while it's running (in park). If you find a place where the engine's rpm changes, higher or lower, you might have a leak there.

 

thx for the help ill threw my crap machanic these ideas its the 30v v6 and when it ideals around 1k the needles bounces hundreds of rpm like from 700-1k and when coming down from 60mph it skips down 200-300rpm at a time

 

Are you talking about the solenoid rack at the top rear of the motor? There are a couple solenoids up there that have two or three lines coming in on Y-junctions. If that's what you mean, I can believe that - those lines become very brittle and break easily. A good DIY preventative maintenance would be to replace the OEM lines with silicone lines so they maintain flexibility and don't crack.