When I accelerate from a stop, sometimes I get a wierd sensation from what feels like the rear wheels. It's almost like the rear wheels slip a little bit before they get traction. Or, maybe it feels like the wheels are being held up by something momentarily, and then they jerk into motion because the engine has already reved. The problem seems to happen more when I at a complete stop and allow the car to creep forward (auto trans.) a little before I step on the gas. I'm pretty sure that it's not a problem with the transmission's computer because I have recently had it reprogramed. Any ideas? Thanks.