Strange compression problem

[shovel52]

I have a 93 22re with 108,000 miles that runs great above idle, but at idle I have a dead #4 cylinder. I did a compression test on that cylinder, not a completely accurate test because the truck was cold and I had the other 3 plugs in, how ever here is what I got. With some one turning the engine over and the plug wires off and throttle held open, I got 5 psi. should be about 145 psi. Test #2, with plug out, and other 3 wires on, running engine, I got 30 psi. should be between 40 and 50 psi. This is a legit test, "Google search the subject" called a dynamic test. This is weird, because when holding your thumb over the plug hole when running, theres so much compression that it hurts. I have researched the subject and most people will tell you "burnt exhaust valve" it does not burn oil, and the plug burns slightly rich. I have read that the fuel pressure regulator can give this symptom. And when holding your thumb over the hole, and nothing, with wires off , compression is escaping some where, if burnt valve, that bad, how does it run above idle?
Blown head gasket would have symptoms some where?? visible or not?
Could compression be escaping back through the injector with incorrect fuel pressure to that cylinder? How would a bad fuel pressure regulator give this symptom? The injector does click when listening with scope.