Used Cars is full of used characters, used ideas, and used jokes, many of which are in astonishingly bad taste. The hero is a low-life automobile dealer, and the movie tells us it's alright for him to cheat his customers, since politicians do things that are even worse. There are several funny bits scattered here and there, to the credit of director Robert Zemeckis and co-author Bob Gale. But when will these proteges of Steven Spielberg put their explosive energy into some worthwhile project instead of wasting it on trivia like this and "I Wanna Hold Your Hand"? Time is running out.