Sounds like it should be the name of a band............
Looks like the main cat has a bad rattle. When it was up on the hoist having the brakes done the mechanic was tapping and sure enough, it was the cat. Nothign seemed loose so I'm assuming the material is a lump in the housing and the cat will need replacing. So, I've got a few questions I'm hoping someone wiser than I can help with.
First, the mech tells me that the only way a cat will break (other than a direct, hard hit) is overheating. So, I'm worrried that something's going on in the engine I need to be concerned about. Now, its the original cat but the car's only got 4,000 original miles. I'm sure the engine's been run a lot more than that over the years with the car standing still though. I've got the v4.3 chip on the car and I run 94 Octane fuel which likely has a max of 10% ethanol in it (all we can get here if you want higher octane levels). I don't see the engine light on ever (except when starting of course). Could I have fried my cat with the chip or fuel or something else or is it possible that Old Man Time just caught up with it?
Secondly, the rest of the system look fine with little or not rust at all. So, I'm thinking of replacing the main cat with one that has a 2.25 diameter, having reducers on each end to mate to the original exhaust (if that can be done). This is all in the hopes that when i do replace the exhaust, i'll do it with a 2.25 system and salvage the cat if still good (which it should be as we're only talking a few years until I do the whole system anyway most likely). Anyone see any issues with this plan?
Many thanks as always!

