or its a burned valve thats? causing car 2 randomly misfire. had spark plugs checked and replaced all 8 coils. checked for vaccum leaks, checked and seen did i need a valve cover gasket. have checked everything possible and still no answers. so was told that i might have a burned valve but was also told if u have a burned valve that the car would smoke out of the exhaust pipe. need help. this is last solution or jus gonna trade it in.