Hi - am new to this group. Bought a certified preowned 2001 A6 2.8 last fall. At that time the car vibrated at and above 65 mph. Theyfixed this with a front end alignment. In Feb. I blew a tire on a pothole, resulting in a bent rim on what is now my spare tire. Got a new tire, all tires were balanced, front end re-aligned, no problem. Then a couple of months ago the car started vibrating at 65 mph again. Took it back to Audi a week ago, got a tire balance, no problems. Then ONE week later, it started to vibrate again at 65 mph. Obviously something's going on to make the car vibrate again - and it's not like I'm off-roading with the car or anything! I'm just driving it on normal highways. Any suggestions of what I can make sure Audi checks out? TIA!