I changed my headgasket and when I accelerate, the cel blinks at me then goes away. The spark plug on the cylinder where the hg blew looks different than all the others. I think its safe to say I need to replace all of them right? And if that doesn't fix it, then coilpacks? I searched the forum and came up with this as my best course of action. I think the plug is fouled. Any other ideas?