threw code P0420 bad cat

[CanadianEh48]

getting rattling sounds from my cat, and it just threw a code...time for a new one! im thinking a high flow one? http://cgi.ebay.com/ebaymotors/Magn...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

would this be what i need? my exhaust is stock right now

 

[Drift]

That will work. . . For a little while, high flow cats usually don't last very long. Just throw a non-fouler in there for now and don't bother replacing the cat. Save the $70. Clear the code afterward, if it comes back, then replace the cat.

 

[CanadianEh48]

haha no way im not replacing it...it sounds like a bad of ****. every time i touch the gas, the pieces of catalyst fly around inside and cause quite a sound.

 

[CanadianEh48]

...should i just gut it?

 

[Dinzdale40]

gut it plus defouler....i hate earth! /sarcasm

 

[finch13]

Gutting it is the same work as replacing it, except the cost differences. Might as well replace it.

 

[Drift]

...should i just gut it?

Replacing it with a straight pipe is a better idea, but you can gut it if you want. When gutted it creates a weird resonance, something about the expansion and immediate reduction in size. Its not too bad though, very tolerable. If you do gut it remember to replace the ring gasket in the down pipe or it will leak like a sieve and sounds like crap.

I know the exact sound you're talking about. I fried my cat spraying nitrous up a mountain in Arizona. By the time I got to Sedona, it sounded like I had bag of marbles in my exhaust.

 

[CanadianEh48]

what are the pros/cons of defouling my secondary O2 sensor? reduced fuel mileage? running too lean/rich? any adverse effects on performance?

 

[Drift]

what are the pros/cons of defouling my secondary O2 sensor? reduced fuel mileage? running too lean/rich? any adverse effects on performance?

Cons: nothing

Pros: No CEL.

 

[finch13]

Cons: nothing

Pros: No CEL.

Correctomundo, I've had this for a while because my cat is out... no CEL for a loooooong time.

Secondary O2 is only there to monitor cat function, it does nothing else.