I have a drive line vibration between 48 and 60 mph. I have had the wheels lazer checked, and are in tolerance, I have installed new engine mounts, the car vibs with the engine at idle at these speeds. I have put a set of tires and wheels from another car which rolls smooth on my car to try that, same vib. I changed the pumpkin to a 54, so I could drive it on the highway. I currently get 70 mph @ 2000 rpm. I really like this 40 buick, but the small vib drives me crazy as that is the speed most traffic travels at in my area. Has any one experenced this and what is the cure.