Thanks for the tips.
The jeep does not have a EGR and all the related wiring was removed from the harness long before I installed it years ago.

I forgot to include it in my original post, but one of the times I had the laptop hooked up, I applied vac to the map sensor and had my wife watch the screen while I moved and wiggled the harness under the hood. She said it never moved.

I have had wires do strange things in the equipment I work on over the years (I am a small engine mechanic). Lots of intermittent issues and they are always the hardest to trace down.

My local junkyard is about a hour away, but I have a gun show to go to in a couple weeks in the same city it is in, so I plan on stopping by there and picking up a pigtail for a ecu so I can have some spare pins.
I will then make and run a new temporary wire from the map to the ecu and see what happens.