Any error codes? How is the battery connection on the passenger side? The PCM uses the ground right from the battery. How the alternator? A few have found that the alternator diode can fail causing noise in the power system which will cause this problem. You can go to most part houses and have you alternator tested on a bench for free but be sure to have the diodes checked! Some suggest adding a ground to the APPS sensor... But I don't suggest it... The fact remains that the truck ran all these years without and now needs wiring mods... Highly unlikely... But I would double check the connectors though... The engine ground for all the sensors and such is behind the starter and requires the starter to be pulled to inspect this ground.