4.3 Vortec Engine Stalls

When the temp outside is hot, and I am traveling for an hour or so, all of the sudden my engine begins to stall and eventually just shuts down. If I sit with the engine off for a while it will start and be ok, but this only happens when it is hot outside. Cold weather it runs great whether I am towing or whatever. Any ideas?

What year vortec?

I had the same problem with my 94 astro 4.3 Vortec. I'm still not sure what the problem is. Changed the fuel pump, both fuel filters, coil, spark plugs and wires, distributor cap. At this point, it wouldn't start at all, even if it was cold. It was only after changing the gas line that we got it to work.

i had the same problem i changed the map sensor and i have had no more problems