Im new to the forums... My name is Kevin. So I've had this 2003 CRV 2.4L (k24a1) just sitting around for about a year because I never had the time to do anything with it. We totaled our 2016 civic so I decided to save us a car payment and I got talked into rebuilding the CRV for my wife. The rings were good but one of the intake valves had a hole in it and the cam journals didn't look good and it was showing 120psi on all but the one cylinder that had the damaged valve. I invested in a new head and started replacing sensors, plugs and vtec. The car seems to run great but after running for an hour it will foul the spark plugs and when I pull them they're covered in black carbon. It will run fine while the plugs are clean but once it has ran for a while it will start to gradually start running rougher and then it starts shaking because certain plugs are not firing at all anymore. I'm not used to working on this style (no interference) motors. Big blocks and V-twins are my norm. With that being said the trouble shooting process is a little bit different than I am used to. Anybody have any advice for me?