OK so here it is, have a 2000 Mirage DE auto 1.8. I'm getting a PO420 code for a bad catalitic converter. Pulled the part and it doesn't seem bad.....??? Current plan is to replace the part but, seeing as this is a $$$ eater looking to see if anyone knows if it could be throwing a false code.

Facts:
1. has stalled a couple times on cold start
2. if I clear the code it comes back in a couple of days

That's all I got.

Any help is much appreciated!

 

go to a scrap yard and get a new cat and just bolt it on. or, upgrade your exhaust and go with a test pipe. There's a way to wire up the 02 sensor so that it doesn't throw a CEL, but i don't know what it is. google it, or try going to mirageforums.net and search. i've seen it done on a friend's car, but since i've still got the cat on mine i don't know the bypass off hand.

 

ARE YOU SURE IT IS THE CAT BACK OR JUST THE O2 SENSOR

 

Your gonna need a catalitic converter and you wont find one at a junk yard, they usually cut them out for $$$. If you run a test pipe in place of the cat converter you'll need a "dummy" o2 sensor which can be gotten anywhere.

As for the stalling on cold starts, a bad cat converterwont cause that.

 

usually its the sensor and not the cat. i would try switching out the sensor first and then if that fails the catalytic converter. cheapest solutions first.

 

Thanks for replying to a five year old thread.