Well, update number 1 from my mechanic.
Strangely, the gasoline is a weird color, mainly orange? He wants to drain the tank and put in fresh gas. Secondly, the fuel pressure is 35 psi, not 40. The engine is running rich, which puzzles him, as it has low fuel pressure.
He also thinks the lockup torque converter is damaged, as he is also getting the #37 error code. He has seen a bad torque converter cause the engine to stall as soon as it is put into gear. A simple test he wants to try is put the transfer case into neutral, and put the trans in gear. If the torque converter is bad, the trans should spin and not stall the engine! I will know more next week.