Silverado won't stay running

Anything to do with the security system? Fuel pump pressure could be another issue.

test mass air flow sensor with ohm meter and look up what ohms its supposed to read, thatll tell you if thats bad, and your symptoms are exactly what that does when mal functioning, other than that, scan it through the obd2 port and read codes, there will probably be plenty, because 1 part can cause a bunch of others to malfunction

just look for that maf code if you cant test the component but can scan it