Alright...I'm planning on getting the emissions pacesetter headers with catted y-pipe. Will all 4 o2 sensors be used? I saw that only 2 would be used somewhere? if the rear 2 o2 sensors will not be used what is the use of the catted y-pipe...anyway I just want it to pass emissions. I'm planning on getting a programmer as well. Any thoughts or help would be appreciated thanks!!

 

I don't know for sure if it will still use all four O2 sensors. I have the without cat headers and mine only use the forward. The point in using the cats would be to keep it legal if your state requires them. Also some cars smell worse without them.

 

I know the purpose for them is to keep them emission legal. I shouldve posted it differently. Meaning that say only the front 2 are used they read whatever and the back 2 read post cat converter if the rear 2 arent used what sense would it make to even have a catted y pipe despite smell if you cant get a reading off of them? what difference would it make is what i suppose i'm asking? lol might be confusing the way i'm wording it but I cant afford to get rid of the egr and whatever else i would have to get rid of.