Dear folks, My 93 sw2 saturn is making a thump thump thump sound when I drive it. It doesn't make the sound when the engine is running and you're sitting still. It gets faster when the car speeds up. The sound sounds like it is coming from the engine compartment just about in the center (doesn't sound like it's coming from the tire area). What could this be and how much is it likely to cost to get it fixed? The car has 166,000 miles on it so I've just been letting it make noise instead of taking it to the dealer. If it doesn't cost too much I might consider getting it fixed. Laura Watson