I just got a 1998 3.8L Camaro w/ 126k miles and I began to notice an occasional rattling sound whenever I am in gear or rev. It is almost a scraping sound its not too loud but loud enough to notice. Its usually fine but every once in a while I hear this rattling/scraping and I have noticed it happening more and more often...any suggestions would be appreciated...thanks

 

does by any chance it sound like, a piece of metal bouncing around a coffee can?

 

Kind of, id say more scraping around the can, or a very small or light piece of metal bouncing around fast...its like a ping or a short rattle sounds like something is being scraped lightly.

 

maybe it could be a bad cat. or an exhaust problem. my cat did that, when it started to fall apart. no cat anymore though.

 

Maybe a loose exhaust clamp? Bad cat as was mentioned?

 

how about a spun berring. does it sound like that. or is it external from the engine. Have someone rev it while you listen with the hood up.