Factual error: When Jimmy hot-wires the Lotus for the last time, he touches a red wire to a black one, the starter engages and the engine starts. Then he twists the two wires together. This would result in the starter running constantly, overheating it, and burning it out. A competent car thief would know never to do that.
Continuity mistake: At the end of the film, Jim Belushi dresses as his mother to trick the warden and enter the prison. After he enters, he changes clothes and reemerges as himself. The bright red nail polish he had on is now completely removed from all his fingernails, yet at the same time he forgets to wipe his lipstick.