Cranks, starts, dies
 

2000 K3500, 7.4l, auto
I disconnected the battery for a month.
Cargo light wouldn't turn off.
I removed the light and reconnected the battery.
Cranks fine, fires, but dies.
Checked the fuses. All good.
No codes.
New fuel pump, fuel regulator, cap, rotor, wires, plugs.
Any ideas????

Found out there is an anti theft system in the ECU.
There is a procedure to reset it.
So tried it again this morning.
Started right up with out a problem.
Strange.