The other thing to check is the foam on your steering wheel. I used to have a similar problem on a Hitec radio using an after market wheel. Sometimes the foam on the steering wheel will move and push up against the front of the radio case causing the steering wheel to bind or stick in a spot or even move a little slower. It can cause the steering not to return to center as well.

On the other hand, if it did take an impact you can pull on the wheel to free it up, but it's just a band aid fix for what's really wrong. If you do have time and a few bucks, I would send it in to make sure the steering is fixed properly.

....and if you have a few more bucks you might want to think about getting a protective case for the radio.