Your getting wild with this in terms of thoughts.
It's an engineered system controllled by the computer.
Ox sensors won't shut down the engine under any conditions because it's not the type fault to leave a truck stranded.
When they don't work the program substitutes fixed fuel tables to allow the motor to run but 'does' set a code to tell you there's a fault.
The fuel pump is under computer control. It doesnot run just because the ignition in on without the motor turning over.
The computer sees the crank sensor signal as the motor rotates and signals the computer to supply a ground to the pump relay among other uses the signal has.
The relay closes it's contacts to pass power from a fused source.
When the motor stops the pump stops.
In the power lead is the crash sensor.
The whole system is designed to prevent feeding a fire should there be some accident that causes a fire or could feed one.
Reseat the cranks sensor connector to be sure it's not a source of the issue.
Seat check the relays and fuses for corrosion
You can see the crank sesnor is the start and reference for all that goes on after cranking begins.
Otherwise you just have to persue all the aves that would shut the motor down.
Total lack of fuel, total lack of igntion, injectors' electrical feed, cam position sensor going open etc.
Until you find the failure fuel or electrical, you have nothing to go on.
No amount of guessing will help unless you get lucky.
Since before 1995 or so these systems has gone way beyond the ability of most owners that have no idea how things work, to service a fault unless some luck plays a part.
It's no better with any other make.
Were here to try to bridge the gap. Sometines we can sometimes we cannot.