I just got the heads off my engine and found the obvious culprit. Cylinder #4 is nice a clean while the others have major carbon buildup. Now again I am not an expert but I would think that if the cylinders were firing and running properly that they would be nice and clean, no carbon. You can see in the pics the nice clean piston and the others as well as the valves on the head. So why the hell do I have so much carbon buildup? Obviously I had a head gasket failure on #4 and it is clean because the water/coolant kept it that way. Please help me as I am naturally concerned about the carbon buildup.