Hey guys so to make a long story short I bought a header/dp combo from someone and installed it on my 07 LT 2.2L unaware that the cat had been completely gutted. Just had my car in the shop for a valve job and used the recommended spark plug nonfouler to gap the o2 after the cat, but two days later the light comes back on with a 420.. Should I use two nonfoulers or a washer to gap it more or what's everyone else doing I have got to pass inspection and get rid of that stupid mil!! Please help thanks guys

 

Is your defouler an angled bung? Those are the only things that ever work but I'm not sure you will get anything to work with no cat at all. They are used mainly for high flow cats

 

try a vibrant defouler that's a 90* bend. If that doesn't work, you either need to get a tune or go back to stock downpipe. Even a high flow catted downpipe will often throw a code.

 

My high-flow catted downpipe does this. I drive it anyway lol. Then again I don't have to have an inspection.

 

vibrant o2 defouler worked PERFECT for me!