Engine/Transmission (1998.5 - 2002) What is wrong with my truck?

[NDaniels]

Well my tst box did the same as yours and it turned out to be a bad diode in the alternator. Mine would feel like a miss and that was the box defuling- green light flickering. Finally got bad enough that I could duplicate it on demand (high revs part throttle). I read about some others that had this problem and followed tst trouble shooting guide. Replaced the diodes and brushes in the alternator- problem solved. I have also read where someone else fixed it by installing a diode in the pm3s power wire. I don't know if this is your problem, but I hope this may help you out, Nick.