Vibration Only When Accelerating...
 

Hey Everybody -

Tomorrow would be 3 months since having my 2002 3.0 Quattro. With 90k now on the car it is suprisingly fun than many cars I've had before. However, there has been a slight vibration on the car. When driving about 40 mph you start to feel the car kinda start shaking. On the freeway it gets worse. However, you let off the gas and it drives like butter.

Today I got the wheels balanced and alignment done which all came out great but the rattle is still there. Audi has told me though that the lower control arm bushings are torn... is this the reason? I'm going to replace the bushings ($1198.00)...eventually, but this is the reason? I figure if it was the rotors being warped then you would always feel the vibration when off the gas.

So now I have it down to what I've seen on here to be a normal issue, the CV boots, or the now apparent problem, the bushings.

Any ideas?

Cv joints or a mount, either motor or transmission. Prob a joint though.

Unrelated: Has your timing belt been done?

i have the same car and had a similar problem. for me it was just that i needed new tires. 2 of my tires (the front ones at the time) were borderline dangerous, and the other 2 were almost worn also, so i replaced all 4. definitely a big difference.

something that might also affect you, i was told my front motor mount was damaged b/c you can easily see a piece of it hanging off, so that also might be a contributing factor.

i'm going to wait for the timing belt change to take care of that though to save on labor. i'm at 71k miles right now on my 02 3.0 Quattro.

edit: just to answer your post, i would say that my vibration is definitely gone since changing the tires. mine would also start vibrating between 40 and 65mph, so i would definitely check the condition of your tires.

Thanks guys. The wheels and tires are all new on Kuhmo Ecsta ASX tires. They were all balanced yesterday and with the inspection found them to be in great condition.
Im not sure if the car has had a timing belt job done actually. How much do those usually run? I too thought it was the cv joints.

Actually I had a full car of people (rare occasion) and the vibration was much more noticable than before I picked them up. Does that mean anything?

The tb jobs vary, i was quoted 1200 by a dealer. Find an audi shop and it should be much less. The job is very important and if youre at 90k i would get it done asap. If the belt breaks it takes the entire motor with it.

Will do. I had an Acura Integra Type R before this and it was much easier to do a timing belt job on a honda engine. There's barely enough room to even get to the spark plugs! I drove the car again today and like I thought, when theres only me in the car the vibration isnt as noticeable. However with a packed car it shakes like its going to fall apart. However when turning the wheels and accellerating I feel the shake no matter what.

That's gotta sound like the CV joints then? Because I heard that if it was the boots you'd hear a clicking.

Found out it looks like the inner CV Joints. Found this article (http://www.geraldstires.com/Services/CV/cvjoints.htm). "The symptom for a failing Inner CV Joint is a vibration as the vehicle is accelerating. To check for a bad Inner CV Joint, drive your car up to 4-50 mph and note if there are any vibrations during the acceleration process. If there is, remove your foot from the accelerator and then note if the vibrations disappear. If they do, then you probably have a bad inner CV Joint."

That's exactly my problem! Now to replace two axles...

Well I had the CV Boots checked over at my Service Shop. They say that the joints and boots are fine and that its actually the hub centric rings that came with the aftermarket wheels.
The wheels were originally on a 1999 VW Jetta VR6, which I didnt know. So I'm thinking the hub sizes differ? Does anybody know where I can find the hub sizes of my '02 A4 3.0 Quattro compared to a '99 VW Jetta VR6?

90k miles without timing belt replaced is very scary. Those Audi timing belts really break. If your car hasn't done it yet, make it as your FIRST priority. Make sure it also includes water pump, thermostat, rollers... etc.

The T-belt for a 3.0 goes for around 1500 bucks average. And like Kchao is saying, 90K is like the limit.