suspect cat converter

[alfaloco]

Just as a cross-check on my own troubleshooting, please tell me what are the classic symptoms of a clogged CAT converter?

I appreciate the input (output?), Alfisti.

[TS Dude]

Not too sure about symptoms, but I remember reading somewhere if you suspect the cat is clogged up then try removing the 02 sensor and start the engine. If you feel exhaust pressure coming out of the empty O2 sensor hole then it is likely your cat is clogged.

See how it goes

[alfaloco]

Thanks for the reply. Based on the discoloration and hissing I hear from underneath, I'm saying I got a bad cat converter. Others have given me the same kind of symptoms, too.

Now all I have to do is find one that fits at a decent price!
That may be the toughest part of the job.

[turbolarespider]

If it were totally plugged, your car would barely move.

Partially melted, your performance would be low.

BTW, if you think you toasted your catalyst, you should fix the problem before you toast another one- they don't melt with age- but via misfires.

Age just makes the catalyst less efficient.

Eric

[alfaloco]

Sure- no doubt about it, the O2 sensor is getting replaced regardless, Eric. Plus, I'm going to check out the voltage values at the new sensor to make certain I'm within range. The way this problem developed, and the way the performance went downhill so fast, I suspect the O2 sensor allowed things to go either rich or lean. From the discoloration, I'd have to guess lean.

The last thing I want to do is to do this job twice! Thanks.