My 1988 chevy 2500 has been so reliable until it stated to stall.

Right here 1988 90 Chevrolet Pickup Alarm Remote Starter Keyless Entry Wiring

The first thing i would do is check the fuel pressure it should be 9-13 psi with key on and engine off.If its not within these specs then first change the fuel filter and if pressure is still low replace fuel pump.Let me know what you have.

EATHER IS NOT GOOD , ITS FOR COLD COLD MOTORS.. CHECK YOUR FUEL PRESSURE AND GAS FILTER .YOU MIGHT HAVE A BAD FUEL PUMP ITS IN THE GAS TANK!!! . USE CARB & CHOKE CLEANER ..PARTS MASTER # 1736 ..ITS NOT AS HOT AND WONT POP A HEAD GASKET .IF'N I WAS ANY HELP AT ALL PLEASE VOTE.. JAY

on the back of the motor the is a oil sensor and it located on the driver side behind the disturber if that is gone the engine will run and then stall after a few secs right

is there an anti theft system installed ??
if yes it is ingauged

check your fuel filter under the left side of the vehicle on the frame. if this proves to good, your next step might be checking your catalytic convertor. have you checked all of your vacuum lines? one thing you can do is have your friend inside to start the vehicle and while it is idling and the air cleaner is off, look inside at the fuel injector and you throttle it and see if the injector is spraying fuel.

you need to adjust the engion timing

Have you checked the coil

Chances are the fuel filter is bad, if not it's a fuel pressure problem.

check the fuel pressure regulator