Rattling Cat???

Hi Everyone,

I have a 2003 gt with a stock h pipe and I think one of the Catalytic converters is rattling. There is just a small rattle around 2,000 rpm that only occurs when the car is warmed up. I got underneath it and banged on the cats a bit to see if I could isolate it to one of them but couldn't tell if any of them were rattling. I did make sure to check the shields to make sure that it wasn't one of them.

Does anyone have any other ideas, or other things I should try to pinpoint what it is? It seemed to get better for a week or so after I was banging on them but came back this past week.

Thanks for the help

Thanks for the replies. I am 99% sure my cat is stock and it only has 4 cats.

I have thought about taking it off to see if I can get anything to fall out but since it only does it when it is warmed up I figure that taking it off while it's cold won't do much good.

Does it make sense that it would be a cat since it only does it when warm?