Hey guys, new to the forum but have searched a lot of the great information here. Here's the deal, truck has dead #6 cylinder. Has new plugs and wires from previous owner(bought it with skip) checked for spark and has good spark. Misses from idle to red line. Checked compression and here's the funny part, it only makes compression every 4th compression stroke, and when it does it has 130ish psi. Pulled valve cover to inspect the timing setup and found everything good. Tensioner and guide still intact. I then put shop air in cylinder to see if it was rings or valves, with both valves closed and 100 psi of air to the cylinder it will spin the motor until the cam opens a valve. Which puzzles me because if it isn't making compression. I wouldn't think it would turn the motor. It's not pushing any coolant like a head gasket or anything like that. I did inspect the cam and found #6 exhaust lobe has some hardfacing missing but still has full lift and the roller on the follower is a little chewed up but spins fine and no play on the shaft. Valve guide is tight and no broken springs. I just cant understand why it will make compression every fourth compression stroke(held my finger over the plug hole while cranking and felt it) compared to #5 right next to it and that cylinder is good. Thought of a cracked head or something but then #5 should be weak too. Any ideas? The motor has 173K on it and very clean inside. Oh, when I pulled the plug it was soaked with gas so I know the injector is working. Any help or ideas would be helpful, the truck is really mint and no rust which is s big deal up here in Maine. Thanks in advance.