i have a 2001 a6 4.2. i got a slight vibration above 35mph...brand new tires and road force balancing and alignment done.. control arms are good and brand new tie rods... what could be wrong???????

 

motor mounts?

 

Ever consider that maybe your brake rotors are warped?

 

Possible that the balancing was poorly done, I have had tires rebalanced and gotten rid of vibrations more than once. Even good machines can be out of spec.

 

Crappy tires -- I once had a set of new tires that balance perfectly and there was a vibration that would not go away. They changed all four tires without fixing the problem so I had to live with it - They were not cheep tires....

A few years later I put new tires on the car (different brand)and the vibration want away.

 

the vibration increases when i take turns at above 45mph..the tires are directional tires

 

I had a similar problem with my wife's car when the front axles wore out. When the joints get sloppy, they can cause all sorts of interesting vibrations.

 

Where exactly are you feeling the vibration? Steering wheel, Seat, pedal...

My steering wheel wobbles slightly sometimes and sometimes not. I think it is control arm related.

The Engine mounts vibrated through the brake pedal at a light then go away under acceleration.

Warped rotors will feel worse when you step on the brake pedal.