Well, everyone was virtually spot on.
End of story: When I get out tomorrow morning I'm picking up my truck from the mechanic.
Didn't get to do the work Monday... called in to work Sunday so Monday was way off. Ran to pick up a Craigslist paddleboard downtown.... About halfway down the interstate wasn't wanting to go faster than 50 without a bit of a punch of gas.... did it again... then a sudden tick-tick-tick-tick-tick and a burning odor.
Played that game before, wasn't about to screw around to see what happened. Got it on the shoulder and idled it (yes I know) off the next exit.
Couldn't find anything immediate, but did notice it was wet on the front of the block.
Let it sit a bit to cool off in the rain. Oil level was on the lower side of full, color and consistency was good. Didn't work too hard at nailing down the source of wet, just no dangling hoses or blown stems/necks obvious. Tried a quick turnover of the engine and that did NOT sound good. Left it alone and flatbedded it.
That was evening. Left a msg for the mechanic. At 1130 the next morning he left me a message-- all done!
Misfire on #6, blew the plug out! (Says he's rarely seen it and he's been around, and a couple small ideas why.) Melted the coil. He pulled the coil, cleaned it out, re-tapped it (couldn't get the new one to seat), new coil and plug, topped it off-- voi la!!!!!!! Smooth idle. (clearly I did a pretty poor assessment under my frustration if I couldn't see that)
He ran a pressure test after me talking about the disappearing coolant... a couple of minor leaks at the main hose and at the water manifold that I disassembled and cleaned up last September when I replaced the water pump-- enough to be slow enough to leak and evap without dripping down or leaving obvious residue.
He's admits it's not 100% on the coolant leak right this second, but said he's seeing nothing else that indicates a head gasket at the moment or reason to dig deeper until I notice it continuing to happen.
Way out of my scope of practice and skill, even as simple as it would be to learn it all. Heck, the re-tapping and the pressure test alone were worth every penny-- $350 for the whole gig!
Guess God took that one out of my hands out of pity of me spinning my wheels... would have been another 2 months for me poking around and back and forth!
Keep an eye on it for a while and see what happens!
Thanks gang.