While stopping the car, it thumps as if the engine is hit by something. It is definitely a physical as I can hear the sound and feel the vibration. It doesn't happen all the time. It happens about ~30% of the time when stopping. It is not getting worse or better. It is consistently doing though. One of my friends told me it may be skipping a gear when the auto transmission downshifts. Dealer says they can't reproduce the problem (I never trust the dealer here; schumacher or whatever). They are awful and the car is awful. Bad buy.