Dude you got to read my thread. I just posted it a couple days ago. I just installed my custom intake and DT headers a few weeks ago. After, a couple hundred miles I still don't have a check engine. Some of the 4 bangers guys say it comes on automatically, but then Slytuna said it rarely ever comes on. So when it does you just clear it and it shouldn't come on for a long time. I've been running the headers for a couple weeks now with no code surprisingly. But I also bought a cheap $35 dollar OBDII code reader from costco that I leave in my glove box. About the cheapest one you can find and I know it works cause I used it on another car with a check engine light. It lets you read the codes so you can look them up and allows you to erase them. So Im just reporting that after a couple hundred miles my CEL hasn't come on. And I love my 4 banger now with the headers, CAI, and exhaust. I talked all about it in this thread here. http://www.clubfrontier.org/forums/...e-doug-thorley-headers-flowmaster-40-a-54714/has any one figured out how to run these headers on the 2nd gen 4 banger and not throw a code?