Hi, 1st off I read around and I think I might have a bad cat, but im not sure.
So I have come here to ask the pros


I have a 2000 civic ex 5spd 150k, stock, the car sputters around 2-3K rpm and the check engine light was on when I bought it, the owner said it was because of the o2 sensor and he gave me a new universal Bosch one, I have replaced that in the primary spot, while having my battery unplugged but it came back on a day later...

I've replaced the distributor and rotor, and spark plugs..

I went to Autozone last week, and had them check my codes, I got the P0420 and P0430 or whatever for Bank 1 and Bank 2. Shouldn't the Bank 1 code be off because I changed it? Should I change my secondary o2 sensor? Or just do the non fouler trick?

The car does sound more loud than it should, is that from a bad cat?

Thank You.

 

P0420 is more than likely a bad cat. You also may want to check for an exhaust leak as well in the exhaust manifold and piping to the cat. If there isn't a leak more than likely your converter is bad. You shouldn't have a P0430 as that is for dual catalytic converter vehicles so maybe that was a mistake. 420 is not for the primary O2 so unless you had a P0135 code you should be fine with the O2 you have in there. I would have autozone reread the codes, clear them and see which ones if any come back, post that for a proper diagnosis.

 

Do you have access to a back pressure tester?

 

I doubt it if he went autozone to scan codes. Beside P0420 without other misfire or performance issues usually indicates a poor performing cat not a clogged cat.

 

Thanks for the replys guys, I did the non fouler trick on it yesterday and it runs wayyy better! Smooth revving all the way up. Check engine light is still off after a 10 minute warm up and a 20 minute drive, took it out for another drive last night for some fast food, and still nothing *knock on wood*
It doesnt sound as loud too. And I used 2 of the non foulers.