heres the cure: http://forums.evolutionm.net/showthread.php?t=114931

 

Nice! Thanks.

 

reason is because most downpipes eliminate the cat. So theres where it commes from

 

But what if you put on a high flow cat? Why would it come on then?

 

beacuse a hi flow cat is less restrictive so the rear o2 sensor will get a higher reading so it will sense that you have a bad cat.

 

it depends on the type to, because there are some high flows i believe that are designed to still do all the emmisions control and allow it to breathe allittle better, but i doubt those will give you anywhere near the less restrictive ones. I would just go with a straight through system and either an 02 sim or what jeff is trying out

 

I have a 3" turbo back system and I have never had the CEL go on. The only time it went on for me was when I had a misfire.

 

you have no cat and you dont have a CEL, something is wrong there

 

i never had a cat on my car and it didnt throw a code. maybe its b/c i only have 1 o2 sensor.

 

yea usually its the second o2 that is after the cat that should throw a code