car undriveable. I am thinking of buying a 1990 535im. It is not driveable. It starts right up but when it gets gas it stumbles and rattles. No Smoke clouds. I'm guessing a chain or tensioner but would love to get some advice from the pros. I have a '91 525 which I love and may get another. But this time it will be a 535im. The car has 233k and is in good shape. I like project cars but how much of a project? What do you think? Thanks so much. Drew are you out there? b