I have some vibrations in the rear when going about 60-70 mph. Did a tire rotation and still had the same vibration. Had tires balanced and still no change. Before I take my car to the dealer I would like to know if anyone else had the same problem or maybe give me some advice. I have a 1998 XJ8 VDP.

 

I have a similar problem. I recently purchased a 2002 XJ8 Vanden Plas, like new condition, but had cheap new master craft (crap) tires on it. I have a vibration that started at 35mph, at 50 the steering wheel would begin moving back an fourth, at 70 there is a constant high speed vibration. I put new tires on had an alignment done and balanced 3 times. This helped the problem, but there is still vibration above 35mph. I took the car to a Jag specialist, the acknowledged the problem, but said that is how some of the cars drive. At this point I am very disappointed and regret my purchase. They did say that there is a Jag bulletin that says that references my problem, and the best solution is an on car tirebalance, which only a few tire people have.I will try that next. Anybody else find a solution to this problem?