Well I've officially started working on it, luckily they had bought a 99 truck FSM so I've been researching. I noticed the TPS (APPS) is a 6 wire deal, what the hecks with that . And I've been looking all through the book but I haven't found how to test and diagnose the APPS. Why 6 wires, I've always seen 3 ?

So I'm guessing the functionality is the APPS sends its signal to the comp which will control the fuel pressure from the high fuel pressure pump changing the fuel volume yes? If the APPS turns out not to be the problem, could the fuel pump have an issue?