[dwalmop]

It sounds to me (if your steering wheel is actually moving back and forth) that you are starting to get a ply separation on one of your front tires. Take it to a good tire shop and they'll tell you. Also, go out and take a good look at your tires to see if you have one particular spot or area that is more bald than the rest of the tire, if so, then that is for sure your problem.