Can anyone help identify my exhaust noise? The car is an 89 SC with 5 speed with 160k miles. The exhaust appears to be the stock system. At idle the noise seems to come from the cats or resonator. It sounds kind of like a rattle. I don't if the cats have broken loose inside or if there is a problem with the resonator. Would like a new exhaust but must first fix brake problems and get it to pass state inspection.