My truck was doing it right before it tripped 100k miles. Found out the PMD was bad, replaced it and put in a new EProm. Problem solved. By the way it was the eighth time the dealer had to replace the PMD, and I was on the third pump. Then I found this site and been smooth sailing since (Knock on wood).
Bbudus
94' GMC K2500HD, Heath chip, -1.94, Turbo-Master, AFE Cold Air Intake, Bosch High Flow Injectors, 3" Exhaust all the way back, 4.5" chrome tip(exhaust sounds sweet), Heath Turbo Down Pipe, Heath Crossover, IssPro gauges, Three Pod Piller, 98' Cooling Mods, DMax Fan, High output water pump, DSG Oil Cooler, Heath PMD kit, Light kit with high output bulbs(very bright...finally)