It's shaking; that's the problem. For a better diagnosis, you'll have to hold your computer closer to the car so we can see it.
If the entire car shakes, suspect a rear wheel or tire problem, bent wheel, out-of-balance tire, broken belt in a tire. If the shaking is in the steering wheel, suspect similar things with the front tires.
Typically, you'll feel a broken tire belt at lower speeds and the steering wheel will wobble back and forth or you'll feel it in the seat. Same thing but less severe with a bent wheel. At the speeds you described, a simple out-of-balance tire is likely. Balancing weights can fall off, or there could be impacted ice or mud on the back side of a wheel.
All of these problems will show up on an electronic wheel balancer.
Wednesday, April 8th, 2009 AT 2:56 PM