Well **** me sideways...
Problem came back this morning on the way to work. On the way home tonight, CEL came on and flashed for about 5 seconds and went out - checking with my cheap scanner, I got a "P0300 Cylinder 1 misfire detected" code. Checked it out when I got home - plug is not fouled out and the misfire does not follow the coil pack when I move it to another cylinder.
And, the dealer is booked full until next Friday. Truck is currently undrivable and the only loaner they have is a PT Cruiser with 400k miles on it that needs 1qt of oil every time you fill the tank. Can't pull a 7500lb trailer with that thing and none of the rental places around here have trucks, it's all cars and CUVs (not even SUVs, just the under powered wanna be versions).
Really considering trading it for an unsold 2016 EcoDiesel crew cab after this...