Well, I can throw in 2 cents…but I am not a mechanic, but I did stay at a Holiday Inn Express last night.
Have you replaced the fuel filter located inline below the driver’s door?
See…from what you have said, it could be so many things.
If it only quit after it runs for a few min. then I would say gas starvation.
But you also stated that sometimes it doesn’t even fire up, which sounds more electrical to me.
If it were me I would start at the Fuse box and check for corrosion….just pop the fuses in and out and see how they look.
After you do that I would look around the battery box for wires that are corroded….and could be giving you an intermittent connection.
The next place I would look would be the Hot wire running from the Battery to the starter, sometimes they get up next to the exhaust manifold and ground out …and when that happens nothing works.(and this has actually happened on my 92 C1500)
Hope this helps.