This seems to be a common problem, and from what I can tell it seems to have different solutions in different cases. Here's the lowdown:
1995 Mitsubishi Eclipse GS 221,000 Body/Trans Miles 127,000 Engine Miles (Engine was pulled out of a wrecked '99 Eclipse GS with 40k already on it, rebuilt and placed in my car) Purchased in 2002I believe this car has vibrated at highway speeds from the day I've had it. Usually around 65 mph. It's completely fine at any speed below 65. About 4 years ago I had the front tires replaced, and the vibration seemed to disappear for a while, though it was still noticable if I pushed the car to around 80 mph. Took it into a dealer yesterday (march, '07) to have a bent rim replaced, and they said that the belt in my right front tire had separated causing a flat spot on my tire. They replaced the tires, balanced them, and when they tried to do an alignment they found that one of my tie rods was rusted and siezed and needs replaced. That was gonna be another $200, so I declined hoping the vibration will have disappeared with two new tires and a new rim.
The vibration HAS lessened substantially, BUT is still very subtle starting at around 70 mph, and becomes worse increasing in speed (only had it up to about 81 mph). Anyone have any ideas or a similar problem? Could the alignment be causing a vibration this severe with brand new tires on the vehicle? I just have this feeling that it's gotta be something else, since the problem seems to be dampened with new tires, but slowly creeps back over time.