The /6 in my truck is having a problem I have not encountered with any vehicle before. Engine supposedly has about 112k on it. It sat for about 10 years and was started occasionally according to the PO. When I got it the intake valve in cylinder 1 was very sticky and in cylinder 4 was a bit sticky. Cylinder 1 intake pushrod was seriously bent. I removed the valve train and used a tube down the intake runner to pour several ounces of ATF into each intake port and let it sit for a week. After that I reinstalled the valve train, new push rod, took the plugs out, and rotated the crank by hand then by remote starter. I did a cold compression test and averaged about 100 lbs/cylinder except cylinder 1 which had 0. I poured about an ounce of oil into cylinder 1 and in 3 revolutions got to 90 lbs. On the 4th revolution it had 15 lbs and on the 5th revolution it had 0. I still had the valve cover off and could see the valves moving properly. At this point I figured (hoped) the rings were stuck and I poured a mix of acetone, MMO, kerosene, and ATF into the cylinder with the piston bottomed and let it sit for another week. I turned it over by hand then by remote starter (got an ATF shower) then another cold compression test. 0 compression. A friend suggested driving it a bit and it might work loose. I did and it did. I lucked out I thought.

This is the current problem that has me a bit puzzled. Cold, the cylinder has no compression. When I crank it the starter speeds up every 5 revolutions. After it warms up the miss mostly goes away and it runs ok. I pulled the ignition fuse and cranked it warm and the starter did NOT race every 5 revolutions but cranked normally. This tells me that the engine has compression when it is warm.
I have seen this cycle of warm compression but no cold compression about 10 times. Vacuum gauge connected to the intake manifold is generally steady at 19 in/Hg at idle with the occasional, very slight, less than 1 in/Hg flutter.

Not sure what would cause this. Any thoughts would be appreciated.

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'82 D150 Regular Cab AT, PS, MB

Could there be varnish build up on the valve stem? That happened to me after running three year old gas. While freeing the valves they were kinda hit or miss until totally free.

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1975 Dodge D100 225 c.i., HEI, Parallel 2 bbl Motorcraft 2150, 904 auto, 9.25" 3.55:1

Maybe the guide expands ever so slightly when warm? I have a feeling once the stem warms up enough it will stick again though. No magic fluid is going to provide a permanent fix, time for a head rebuild if you want something reliable.