So im tryin to figure out everything before i go tearing through my exhaust. the cat gets gutted. the o2 sensor in the cat gets 2 non foulers with a 1/2'' hole in the second one. the post cat sensor will be taken out throw a code, but the truck should still run right. is that correct?

 

The O2 in the cat get's left alone. The O2 AFTER the cat gets the non-foulers.

The purpose of the non-fouler trick is the eliminate the CEL all together.

 

so the o2 sensor in the cat is left alone? and it will still read right?

 

it SHOULD read normal. Remember, this is a simple way to TRICK the pcm into thinking that the cat is working properly. It's not a 100% guarantee that it works perfect each and everytime.

 

Look at it this way, the pre cat 02 reads the dirty combustion gases. The after cat 02 reads the gases that the cat has removed or cleaned. The trick is when you gut the cat the non foulers pull the aftercat 02 sensor out of the flow of dirty combustion gases and trick it into reading only a partial amount of exhaust making the PCM think the cat is doing its job. Only drawback I have found is that the exhaust is smells as bad as the 63' chevy I drove in High School. As smple as I can put it.