I have had this problem just recently- 92 Dakota 3.9L LE
After starting and running for a few minutes, as I back out of my driveway (incline), the engine shuts down. Just as if I turned off the switch.
After a couple of tries at restarting, it starts and runs without any problems for the rest of the day.
Yesterday, after running for about 15 minutes, as I was climbing a hill, it shut down again. It restarted and no problems for the rest of the day.
New plugs , rotor, distributer cap. New fuel pump 5 years ago.

I have not changed the fuel filter for about five years. Had over a quarter tank of gas on all occasions.

Thanks