O2 Sensor

It's possible that the engine was running very rich and the cat clogged up, melted down, and broke into little bits.

Even if this would be possible, could this happen when the car was only running for five minutes (if even that)?

Secondly, I forgot that I should have mentioned that according to the codes, they say that it's running lean, not rich and the voltage for the O2 sensor was low (below .2 volt). Not too high.

Travis, But that is the point: if the O2 sensor failed and was telling the ECM that the car was running lean when it was not, the ECM would INCREASE the fuel to the engine, and make in fact run rich even if the O2 sensor said otherwise. This would give the effect you mentioned while driving to school.

I doubt a short time running in this condition would have detonated the converter, but it might be smart to have the converter checked before your next smog check is due - might save you a nasty suprise.

Regards, Bill Bowen Sacramento, CA

We don't have smog tests in Iowa. But I understand now.

Yes. 0.2 is too low. The O2 sensor was shot and telling the ecu to dump raw fuel into the engine. Partially burned fuel hits the cat melting it down and clogging the exhaust causing steadily decreasing power. It is a classic bad 02 senario. The cat has probably been going bad for weeks. If it started running good again its because there is not much left inside the cat now.