My '03 Tacoma has a little of the same problem. If I am setting still, the steering wheel can move ever so slightly back and forth with no movement of the tires, it's kinda hard to explain what it feels like. I don't notice it while driving and doesn't seem to cause any problems, but come to a stop, I can wiggle the wheel and feel it. Feels like slop in the teeth, but only in the straight ahead position.
