Thanks Joe. I haven't been able to get back to the truck yet, but my current plan is to test the voltage at the coil in the run position. Based on the troubleshooting section in the shop manual and earlier comments above it seems like the problem is most likely exactly as suggested - voltage is cutting out after I take my foot off the starter pedal (the ignition switch is either off or on - no start position vs run position.)
Assuming I confirm the above with testing, I plan to put all the original wiring back to factory routing, "except" I will take the wire that ran to the coil and run it to the relay instead, and run the 10 gage 12v output from the relay to the coil - which is exactly what you are suggesting above if I read you right.
I'll fill you guys in after I get a chance to work on the truck again next weekend.
Thanks!
