When do you know your cats are bad

[kid rock]

totally off the beaten pass i know im sorry!

BUT

i have had 4 of my 6 cats removed 98GT leaving only the 2 nearest the engine, i have recently started to get a rattle from the passenger side rear of the exhaust when i get on it below 20 MPH, is it possible for the cats to break up? and bits rattle there way down the exhaust?

Si

 

[RedDaemon]

I think your engine light would go on if your cats were bad.

yes if they ARE bad, but he is asking if his are GOING bad