So I'm throwing a CEL which, according to the dealer, is "catalyst efficiency below threshold". The mechanic told me the catalytic converter is bad and they're getting me a new one under warranty. Great. They told me I can drive the car around normally without a problem for the next week or two while I the part comes in... How safe am I really? I was racing a Civic Si turbo at the track the other day and after I beat him, he goes to me - "hey, you should tune your car, it's running very rich". My car is tuned, though. And I'm sure the reason he said that was because I was blowing out what looked like white smoke through my rear view mirror from my exhaust. And I've noticed I've been getting crappy gas mileage since I got the CEL.

Is it bad to drive around with a bad cat? if so, why?

Thanks guys.

I thought the cat is a matter of pollution and has nothing to do with milage or etc...

I donno..

That's what I thought. I'm harming the environment. Would there be any damages to my motor though? I friend of mine told me to be easy on the car and not run it hard while I'm waiting for the new cat.

I dont see how it could hurt it, but i know that running rich can hurt the cat, if gasoline gets in there its bad for the cat.
If you get a catdelete header it would be the same thing as having urs broke, so idk.

What exactly is the code? If your front O2 sensor is out of spec the ecm won't pick it up and will use the bad signal and may run your engine rich. Deffinately find out the code. Your car is OBD1 so you can get it yourself.