Quote Originally Posted by Tech5
If it was clogged it wouldnt run hardly at all. he stated that when you get up to speed higher speeds it runs fine without a issue only low idle an low speeds...Not the cat!
You'd be suprised. An ex had a '98 Civic that was idling erratically hot & cold...I replaced the idle control valve/solenoid and it fixed the CEL and it then idled fine UNTIL it warmed up. You'd have to keep your left foot on the brake and right foot on gas to keep from stalling. No CEL's. Replaced the O2 sensors, no change. It ended up being a partially clogged cat.

Normally if a cat is clogged you'd think whether it was hot of cold it would have the same effect. I don't think the material in them expands much to heat so I don't know how or why it was effecting it. Made no sense to me but with a new catalytic converter it still runs fine 2 years later and passes emmissions