What about battery and alternator (serpentine belt).
Check your grounds guys...if even ONE ground is loose or corroded from the block, she'll act up...especially more when warm. Another good place to check is under your console (behind radio), this is where your main ground actually connects (weird yes) but we've rebuilt a stealth and had this problem....turned out to be the ground on the metal chassis behind the radio.
It is most likely the thin wire that hangs off the side of the distributor. They often short out and have cracked insulation allowing them to short out. You can get a spark tested and connect it to on of the spark plug wires and crank the car and look for spark. If no spark there, check for spark at coil wire. If you have there but not at plug, you know the problem is between the primary and secondary system-meaning most likely the cap and/or rotor in the distributor or bad wire previously mentioned. Have you changed the cap and rotor yet? These are inexpensive and will often solve the problem especially when the problem is when it is damp outside. The problem is not the fuseable links on the shock tower, like the other person mentioned. It probably is a loose wire somewhere like the distributor wire.
Had the same problem with my tracker. Replaced the camshaft position sensor(easy to do yourself, takes about five mins.) Now can drive at highway speeds for about a half hour and stop at the gas station and she'll start back up and run fine. Before i had to wait at least 15-20mins before she would start. Also, if your service engine soon light is on take it to the national chain auto parts stores and they will hook up the code reader for free. The sensor runs about $120.
I would take the truck to an autoparts store and have the fault codes retrieved from the computer. Most stores will do the scan for free. I would lean toward a faulty throttle position sensor, but that's just speculation. The fault codes should narrow the problem down. Hope this helped and best wishes.