Truck will not stay running

Sounds as if the IACV idle air control valve has failed. This controls idle speed by bleeding idle air past the throttle valve. If the engine runs okay above an idle I would be suspecting this valve. It is located on the throttle body.

I would also check the throttle body for carbon build up. Very common for it to build up and block the air around the blades and the AIC also gets plugged. Usually a good cleaning does the trick.
This shows the general process.
https://www.youtube.com/watch?v=1PL1S1NNFFY

You're overlooking the most common cause of low idle. The battery was disconnected or run dead. Fuel trim numbers and other data will be relearned as soon as you start driving, but you have to meet a very specific set of conditions for "minimum throttle" to be relearned. Until that is done, you may have to hold the accelerator pedal down 1/4" for the engine to start and / or stay running, you won't get the nice idle flare-up to 1500 rpm at start-up, and it will tend to stall at stop signs.

To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.