Gtidan

When starting the car cold in the morning lately there is a rattling noise for about 3/4 seconds. I'm pretty sure it's coming from one of the cats. Anyone else had this happen to them?

It just started doing this about a week ago. It only happens during the first start of the day. From there on no noise whatsoever which makes be believe it's a cat.

Car has 15,000 miles (2006)

Thanks for any comments