Car only has 60,000 miles on it. Bought it from neighbor who had it sitting in her garage for years. Problem is that the car shakes VIOLENTLY at idle when placed in reverse with foot on brake (Not moving). The RPMs on the engine drops down around 500 rpm. All of the motor mounts have been replaced. The shaking goes away when you rev the engine above 800 RPM. This is the only problem in an otherwise pristine car.