At 09:06 AM 10/14/2008, Jim Johnston wrote...
>I'm trouble shooting a stumbling idle.  I think I've found my problem.
>I
>noticed the exhaust puffing and the muffler had some odd sounds coming
>from
>the muffler itself.  So I pulled the cat and muffler.  I only snapped
>two of
>the three bolts.  It turns out, my catalytic converter has
>nothing  left.
>...
>Would running with an hollowed out cat lead to the muffler breaking
>down?

What may have happened is that the cat got damaged, and the broken
pieces ended up being blow into the muffler. The substrate is quite
brittle, so once it's damaged, the whole thing falls apart rather
quickly. That can cause strange noises, and constrict the exhaust.

My advice is to take off the muffler, and shake it to see if there's
stuff rattling around inside, maybe try to shake any pieces out.