I bought a 1991 Chevy gmt400/2500. Has 181k miles on the dash, odometer stopped rolling. Was told it had a sbc 350 swapped into it with 80k miles. I know nothing else about what was done to the truck.
when I got it a few months ago it drove fine until it shut off on me at a stop sign. No idea why. I couldn’t get it started back up until I put some fuel in the carb. Started up and drove fine a few more times. Now it sits it my driveway because it won’t stay running. I can cold start it right up, it’ll idle for like 10 minutes then shut off on its own and won’t start again. It cranks and almost starts but that’s it. I have no idea how to get this truck running. Someone help lol

 

Gas in tank??????? If so, disconnect coil wire(safety). Is it carbureted or throttle body? If carbureted, disconnect fuel line at carb and have buddy crank it over and test to see if it is getting gas from manual fuel pump. If tb, disconnect fuel line at filter (under truck) and crank over to see if fuel is coming from electric fuel pump.

 

My 93 5.7 did this three different times over the years from a failing ICM in the distributer. Easy/inexpensive part to change. Use lots of thermal paste on install.

 

Mine would act squirrely last year similar to yours, but I had plenty of gas coming to engine. I replace controller too but that didn't solve problem. Finally, I gambled and replaced distributor (original) with an OEM new one and problem went away, at least for now.