2000 K3500, 7.4l, auto
So I had the battery disconnected for a month.
The cargo light was staying on.
Took the light out today, reconnected the battery, and tried to run it.
It cranks fine, fires, but then dies.
Tried it a number of times and does it all the time.
No codes.
Fuses all good.
New fuel pump. Was running fine.
New cap, rotor, wires, fuel pressure regulator.
Haven't taken a fuel pressure reading.
No alarm.
Any ideas????

 

Bad battery?

 

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.