2004 SS.

Do any of you guys know if there's enough real estate to put spark plug non-foulers onto a stock exhaust system for the rear O2 sensor? I want to turn off my 0420 and I'm assuming if it works for high flow exhausts it should work for failed stock exhausts. Getting out of the gas path should work whether it's aftermarket or stock, right?

 

I did this on my 2005 monte an had no problem ..

 

If you haven't done any mods, I'd be curious what's causing your P0420. Could be a failing O2 sensor or a cat (just thinking off the top of my head).

 

Thanks, Jerry.

Maniac, you're correct, I've done no mods. I think I'm broadly assuming it's the cat. I've seen no decline in fuel mileage and I don't get on it enough to know if a clogged cat is affecting my performance. I mainly want the code to go away and I don't have the money for a new downpipe or a tune. As long as it doesn't affect my wallet, I'm happy to hide the problem by covering it up.

 

You can check under your car after a long drive to see if it's glowing, that'd indicate that it's clogged.

defouler should work to help your problem, but not 100% sure if it would to be honest.

 

Got a quick question. Don't mean to tyread jack. But I was changing my oil yesterday and I saw the cat converter/downpipe. And I was wondering would an aftermarket one fit without any modifications. By that meaning the stock one looked tivht in there so. If I were to get a zzp downpipe like how I plan on doin. Would I have to cut anything to make it fit

 

I know for a fact the ZZP one fit's like a glove. Zero issues. Below is a link to my site from when I put a ZZP pipe in my Monte:
'04 Monte Carlo SS - ZZP Downpipe

I got the front in the air and did everything from under the car. Prior to doing it, I hit all the bolts with PB blaster. Everything came free nice and easy. To get the top bolts connecting the DP with the rear mani, I just used some long extensions on my ratchet. Probably took about 1 hour to do.

 

get a stainless steel 90 degree oxygen sensor extender off ebay. Less than $15 bucks. Sounds like your rear O2 sensor is going. If and when you replace it, search the net for a Bosch one. Do not get a universal one that requires splicing the wires. Those rarely work.