I put a k&n in my 2010 duramax and I didn't make it out of my back ally before I got "engine power reduced" as soon as I would drive a bit I would get power back but when I slowed down the message would come back. I took it out and put my NAPA gold filter back in and there was no problem. I guessing the filter was over oiled from the factory and wasn't letting enough air in through at low rpm's.