Originally Posted by JRRF

Are you sure it's not the road? Frequently (especially in a place like FL) an asphalt highway with lots of rush hour traffic can actually get wavy and cause a little shake in your steering wheel. Where I live I know exactly where I'm going to get it -- it's where the road experiences the most stop and go in rush hour, and the trucks wind up having to hit the brakes a lot. That causes the road in hot weather to get waves in it.