Originally Posted by dieselnutnj

what your missing here is that you have a resonant vibration in the car. Drive the car slowly accelerating, and note where you feel the vibration, at what speed. I still think you have a tire out of balance. I have seen many shops do a quick balance on them and they are STILL out. I've gotten tires back that are less then an ounce out but still cause problems. Also, can you physically see the wheel shake when you feel it? Could you have a bad center bearing on the drive shaft? If the vibration is more under load ie accelerating I'd also check the flex disks on the trans and rear differential.