Who's Harry Crumb? (1989)

John Candy is Harry Crumb, the last in large family of private eyes. Unfortunately, big-hearted Harry's bumbling nature has led to his exile from the family for ten years while the family business was turned over to snakelike Eliot Draisen (Jeffrey Jones). Draisen plans on capitalizing on portly Harry's ineptitude when he puts Crumb on the case after kidnapping his own best client's daughter so that he can run away with the client's wife (Annie Potts). But this time, Harry, with a bizarre array of disguises, just might crack the case and prove he's one Crumb that won't be swept under the rug!