Starting issues
Ed,
All of the above suggestions are important to check. I have a '93 with 310K, and had the same problem that eventually got worse. My truck would start right up when cold, but after warming up, and a short drive down the road would not restart. After sitting 30-60 minutes would start again!? Then it got to where it would knock off sitting at a stop light. I checked my ICM at Autozone, and they said looks good, fuel pump was coming on, plugs and wires good, pressure regulator, etc... all checked out. I was thinking, I'll never figure this out. One day when I started it up, there was a loud pop, like a back fire under the hood. The checked it out and found that the hoses attached to the vapor cannister, part of the EVAP system, had blown off, including the two caps that sit on top!! One hose blew off with such force that it was missing about 2 inches!!
To make a long story a little shorter, I got to thinking there must have been a decent amount of pressure on the cannister. I read up a little about it and it is primarily an emissions thing, and stores fuel vapors when the truck is not in use, etc... The Haynes repair manuel suggests to replace it if it is ever damaged. Before I replaced it I drove my truck around without it, and to my surprize no more starting, or shutting down at stop lights anymore! So just to make sure I was keeping my truck legal and all, I bought a vapor cannister at Autozone, or Advance Auto for around $70, plus some hose to replace the piece that had blown up, used the same two knobs that sit on top, and 15 minutes later, Badda Bing! Good to go. That was over a month ago.
Over the course of 15 years, and 310K it got clogged up. I sincerely believe that was my problem, and it was causing some sort of vapor lock.
Sorry to be so long, but hope your truck is fixed, and hope I may have helped in some way.
Peace...
