I got this code read at advanced auto parts. I have searched but did not find any aftermarket situations like mine.

I have had a Cattman Y-pipe for about a year, NO CODES at all.

A couple weeks ago I added a magnaflo CAT from Warpspeed (bolton) AND also a brand new Stillen Exhaust, everything was great for a day and then I got this code. reset it and it came back a day later.

I have cattman y pipe, magnaflo cat converter, and stillen catback. Any opinions of what is causing this?? Thankyou for your help!

 

BTW- this is a 1998 Nissan Maxima SE, I am pretty sure its FED spec car which I read could make a difference with this code.

 

I had it, and it ended up being one of my O2 sensors; the first one before the cat IIRC. It is a very trickey and mysterious code tho, many have been puzzled on it. Search about it as there have been threads on it over the last 6 months or so.

 

I'm no mechanic, but it sounds like an o2 sensor. A friend of mine had this happen after he put an exhaust on his max, and it was his o2 sensor.

 

I'm leaning towards your hi-flow cat being a worthless peice of crap

 

ever since i put on my budget b pipe my rear o2 always triggers, too much air flow ??!?!?!?
I had an upgrade 96 ECU in my 97 and it didnt trigger it. Maybe 97 ecu more touchy.

 

I'm with KRRZ350. You gain nothing with a high flow cat and the magnaflow cat is a TURD. The insides will most likely come appart with in a few months and it is possibly the cause of your code. You may also check for intake leak after the MAF, exhaust leak before the cat, or a bad or leaking injector. Those are the main 4 causes for a p0420 (right bank, Three way catalyst does not opperate properly)