My car shakes while accelerating from 52-60 MPH. It almost feels like the car is shimmying from side to side. It is noticeable in the front and back seat and the dash. The wheel does not shake at all. I rotated my tires and the shaking did not change. The car has new brakes all around and almost new tires. There is no noise or vibration while turning and the inner and outer CV boots are clean and intact. It does it under light or hard acceleration. Nothing seems loose or visibly wrong with suspension at all four corners. Any ideas what it can be?