codysgarage

2015 Tahoe 5.3 with AFM. Had an AFM lifter go bad. Pulled the intake, heads and lifter baskets. Replaced all lifters with gm parts. Had heads resurfaced and leak checked. Replaced head gaskets, head bolts, intake manifold gaskets, spark plugs, wires and coils. Ran for about 15 miles and got P0300 misfire code. Hooked up scan tool and watched misfires and only 6 is misfiring. Removed spark plug on 6 and 4 to swap them. #6 was wet with oil. Did a compression test on #6 and #4 (4 for reference) and 6 is all over the place. Too low then too high. Pulled compression tester out and it was coated with oil. Removed exhaust manifold and #6 port is coated with oil. Removed the head and the #6 cylinder is full of oil. Any help or advice would be greatly appreciated. Thanks Edit