I finally got in the throttle a good bit one time just to see what it would do. It was pretty quick. If it wasn't for the vavles chattering I say its running pretty damn good. Anyway the light stayed on. I was figuring it was some kind of idiot light. I'm wasn't to worried about it I was just wondering how it works. But I guess its just something else to watch on the dash. The truck still has the stock exhaust on it. As soon as I get the valve noise taken care of the stock exhaust is coming off and I'm gonna run 2.5 all the way with no cat and a flowmaster. Hopefully this will be a good enough combo. I have all the tubing and the muffler laying around I'll I have to do is get it bent.