ive noticed over the last week when my car is running int he driveway i can hear a ticking noise coming from the cat. it never used to do that. could this be the stuff inside has broken and is floating around in there??

give it a hit with ur hand and see if it rattles

I'd advise doing this when its cooled down, else with a rubber mallet

The cat coverter honeycomb melted on my 323 turbo due to a failed spark plug lead. It then sounded like a tram going down the road due to the loose bits inside .

If you have loose bits inside your cat, that can only be due to overheating or some impact. So yeh, give the cat a shake and listen for loose bits but don't forget to check why it happened. You can destroy a new cat rather quickly if running too rich due to a failed lead, and that will be costly.

Cheers

could be the outside heat sheilding aroudn the cat

cold had melted it due to running to rich! if so the cheep way to get around it is to knock all the honeycomb out! dont get cought by EPA!