Vibration in 2002 A6 4.2

[James Zwahlen]

Has anyone experienced in problems with a uncurable vibration in the A6
4.2?

My 2002 A6 4.2 was delivered in May of 2002, and currently has 17k miles
on it.  Shortly after delivery we began to notice a vibration most
noticeable between 45 and 55 MPH manifesting itself as a shaking of the
steering wheel and mild to moderate vibration felt in the seats.
Although noticeable when driving straight, it is more pronounced when
making gentle sweeping curves.  It is noticeable at speeds up to at
least 80mph although at a much higher speed-related frequency. At high
speeds the vibration makes the car feel 'nervous'.  I first took the car
to the dealer to fix the problem at 3,800 miles and it has been back to
the dealer 4 times and they have been unable to sort out the problem.
The dealer has:

Balanced the original OEM tires (ContiSportContact)numerous times,
including a higher tech wheel and tire matching.

Replaced front brake rotors (I believe there was a mild warpage of the
rotors)

I replaced the ContiSportContacts under warranty and got the 'new and
improved' ContiExtremeContacts.  Installed at Goodyear.  These new tires
made absolutely no difference in the vibration.

After four visits and 13k miles of dealing with the dealer, I called
Audi Customer Service and they are working with the dealer to arrive at
a solution to the problem.  Both the dealer and Audi seem committed to
arriving at a fix.

The dealer has now tried other tire/wheel sets (all used) on the car
with no improvement.  The dealer inspected and tested the wheels 17" and
they say they are true.  It's taking between 3-5 ozs per tire to get
them in balance but they are balancing.  After swapping out one tire
with TireRack, the road forces are reading between 3 and 10.

They have replaced all four axles.  No good.

The dealer is now looking at the tires again (the new ExtremeContacts
have less that 400 miles on them) and the dealer thinks the tires are
not seating properly on the wheels and 'squirming' on the wheels.
Continental was contacted again for warranty and are inspecting the
tires again tommorow.

Have any of you experienced a similar problem?  Please email me direct
at jzwahlen at houston.rr.com.

Currently,
2002 A6 4.2
2001 S4
1994 Porsche 968

Formerly,
1993 100CS
1987 5000CS TQ
1985 5000S