2004 base coupe with automatic transmission and 37,000 miles. I'm the second owner (live in Minnesota), bought it with 27,000 miles on it, a year and a half ago. Problem has been with car since purchased by myself. Taken to 2 chevy dealers and a vette performance shop (whose owner used to race c4 vettes). All are baffled and at first thought it was due to tires and or wheels, apparently a common problem. Vibration is slight (can't be felt on a road in less than great shape for example) and starts at about 60 mph and continues from there. If it's happening before 60 mph, it's not felt. The vibration lasts about a second or so, then stops for a second or so and then continually repeats. Vette has new tires and wheels, (3) 4-wheel alignments, new brakes and rotors, a half shaft replaced, engine runs great, transmission shifts fine, harmonic balancer ok, everything else has been looked at (again at 3 different places). Was told by 1 mechanic, to just drive car til something breaks, not something I really want to do.
From online research, I can't find any information or anyone else experiencing this exact vibration problem.
I personally think it has to do with the torque tube assembly but due to costs, just to remove, would like to be sure before going that route. All the mechanics have told me that if it was a CONTINUOUS vibration they would figure the torque tube assembly. But with the vibration stopping and starting, they can't be sure.
Any assistance will be greatly appreciated.
Thanks.