OK, I just replaced the NSS, and the truck is still doing the same thing. Just to backtrack, I can jump the starter solenoid, or give power to the "S" terminal, via a jumper wire from battery positive to the "S" terminal, & truck fires up, like a charm.

What am I missing here? I'm questioning my key cylinder now, after NEW ignition module, New starter solenoid, & now NEW neutral safety switch. Also, what are the chances that something in the computer itself, has gone bad.

Thanks!