what would cause my truck to stall

It sounds like the crankshaft angle sensor, main control relay or fuel pump is going out but the be sure lets go over these guides to help us fix it the problem. The should scan for codes as well you could have a MAF or MAP sensor going bad which will leave a code (a bad crankshaft sensor will not leave a trouble code FYI). When the engine stalls lift he hood and check to see if any of the relays are hot in the main fuse panel (PDC).

https://www.2carpros.com/articles/engine-stalls

and

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down these guides and report back.