this started out the customer was driving down road. truck just quit.

Well, you need to narrow it down to spark or fuel problem. Pull a plug and ground it and turn over. Is it sparking? If it is check fuel. If it is not it could be coil, pick up assembly, or coil resistor. Pull wire from cap and see if getting spark from coil, then put wire back,unplug from coil and see if spark from distributor. If getting spark but no fuel, check fuel pump relay or fuel pressure from pump.

Check the fuel pump pressure.. if the pressure is not high enough, the system will not allow the fuel to continue to the injectors or throttle body. I made a tester for fuel pumps myself with just some hose, a few fittings and an isolated guage that goes from 0 to 100 psi and I can change it out with another guage that goes from 0 to 400 psi if necessary. You must connect it somewhere from the pump and before the fuel filter. you may need to turn the key on a few times to get it to build up. Also, be careful on many Dodges of the early 1990's, if you disconnect the battery and you reconnect the ground first then the positive it could reverse the polarity of the pump operation. This will cause the pump to be ON (Pumping Fuel) when the key is NOT IN the "RUN" position and it will turn OFF (Not Pumping Fuel)when it IS IN the RUN position. I experienced this first-hand when I allowed my step-son to help with the car. he reconnected the battery by connecting the ground first, then connected the positive and it arched when he did it which made him flinch and the momentary contact caused the reversal of the pump operation. To fix it, I intentionally reconnected the battery the same way he did which made the pump begin to function properly. Also check that the area that the crank or cam sensor is supposed to detect is free from excess oil and dirt. If the sensor cannot "see' what it is supposed to, it will give the same fault condition.