At the end of the episode, as the were-car hits the lip of the furnace, it's shown flipping over onto its roof. The next scene shows the were-car in the furnace upright, on all four wheels, instead of on its roof, as it should be.
When Bender as the were-car is chasing Fry and flips him into the driver's seat couldn't happen because the Bender car was a hardtop.