I have a 2006 Acura TL with a 6 speed manual transmission. The car has approximately 40K miles. It drives great except that it vibrates (appears to be engine vibration) between 1000 and 1500 RPMs. Anyone have similar problems or know the issue?I did take it to the dealership, but they've had the car for 2 full days now, Supposedly they are trying various things but they still haven't figured out the cause of the vibration.