ECM swapping

[ZeroNthedark]

Since I don't want to leave a thread unresolved, if simply for future reference, here's what happened.

Apparently the truck was throwing a code for a "Speed Sensor" issue when it was shutting off. The company mechanic who had been working on it dismissed it as a fluke... because he'd taken 2 used ones off another truck in the fleet when they had gotten ready to sell it to my friend. After our computer experiment failed, he revisited those sensors. Replaced one on cam, I think, and one on transmission. Truck has worked 3 days straight with no issues. Sometimes it's the simplest things I guess!