2006 Camry vibration

Have your engine mounts checked. I had a similar problem with my '87 Camry. The mounts dry out and crack. As the engine RPM's up it tends to vibrate less so the problem only occurs at certain times. If a mechanic checks them and sees no problem it might be because he's putting your car on a lift ( keeping the car level ) which won't show the cracks in the underside mounts. Have him jack up one side with a tire jack and check the main mount ( center underneath ) again. He might resist but have him do it anyway. Repacing the mounts isn't too costly and it does solve the problem if that's the cause of the vibration.