Hey Guys. I posted a thread about this previously but I wasn't able to track it down so I'm writing a new one . I have a 2012 Civic Si Sedan with the K24z7. I have a skunk2 CAI, Full Race Catless DP, Invidia N1 Catback Exhaust, and a Complete Vit Tune. I've been having a sputtering issue recently and I can't quite figure out what the issue is. I replaced the spark plugs about three months ago and double checked the gap at .044. I had initial done a valve adjustment as the car is pushing 100,000 miles so I figured it was due. So here's the issue. When the car is idling I occasionally get a small popping sound, like a backfire or sputter. It's not all the time, just occasionally. But when i really get on the accelerator, it will sputter and backfire like crazy. When im driving normally it doesn't seem to be an issue. I always fill up with 91 octane (which is the highest octane available in AZ). It's driving me crazy and I threw a CEL the other day. The car just slowed down with a blinking CEL and sounded like it was firing on 3 pistons. I turned it off after pulling over to the side of the road and cleared the ECU. When i turned it back on it ran ok, but the sputtering was still there on hard pulls etc. I've narrowed it down to a bad coilpack, faulty or damaged injector, or possibly the 02 sensors which I haven't replaced since buying the car. I got a brand new MAP sensor with my aftermarket CAI so I don't think that's the issue. I also double checked the valve clearances and everything seems okay. (.009 intakes, .011 exhaust) I'ts so annoying and i do feel that the car is lacking power. Any advice would be greatly appreciated.