I had my whole exhaust system replaced for about 170 bucks the heat sheild...(the outer skin of the muffler) was all rusted and peeling off so i got a new one. Then i drove for a while, the rattle has gotten a little quieter, but still there. I know it has to do with the exhaust also, but it's no the heat sheild. Im thinking maybe its just due to age, cause its a 97 and has 90k on it.