I have seen a fuel pump cause this. I have also seen (twice on dodge pickups) an ignition module cause this, which is unlikeley. Modules usually work or they dont. Check your fuel filter and put a pressure gage on te truck and drive it, paying close attention to the pressure fluxuations and the conditions thereof. Faulty or loose wires in the relay circuit or ASD circuit have been issues in the past for me as well.
Just dont start shotgunning parts as that gets expensive and upsetting.