IF its broke up and clogged -causing rattling sound you should be able to hit the cat with a rubber mallet or the palm of you hand hear the inside sound like rust, or pieces of junk move from the impact. Do it while she's cold not hot.. don't want to crack it if it's actually good.

 

It was indeed a glogged kitty

 

glad u got it

 

I just ordered a magnflow cat system with a flowmaster cat back