Bad Catalytic Converter?

[WhiteFizzo]

If one of the cats on my stock H-pipe has clogged, would I notice on a cold start? Right now when I crank my car after it has cooled completely, i.e. overnight, my car idles fine until it heats up. Once it reaches normal operating temperature, the idle goes to crap and the H-pipe heats up alot more than it use to.

 

[HISSIN50]

If you have a vac gauge, hold the RPM's at 2000+ (but steady) and see if the vacuum reading falls off after 20+ seconds. This would indicate an exhaust restriction, and a clogged cat is likely.

Good luck.

 

[86bluecobra]

if it is clogging usally they rattle around in there. Just tap the convertor to see if it is rattling around. JUST TAP IT. Don't hammer it at all.

 

[Black1987Stang]

if it is clogging usally they rattle around in there. Just tap the convertor to see if it is rattling around. JUST TAP IT. Don't hammer it at all.

I agree with him, mine went a month ago (1 of the 4), sounded like a hammer was floating around in my motor, had noo power, it was so quiet I thought it was bone stock, and you could just tell it was choking everything up. Tapped it and u could hear the honeycomb rattling around in there.