I have a ‘92 D-150 with a 318. It cranks, but sometimes won’t start, sometimes starts but only runs a few minutes then instantly dies. I tested the coil, cold, seemed within specs. Checked for fuel at the rail, has pressure part of the time, seemingly none others. Replaced the fuel pump relay, still the same problem. I replaced the fuel pump last year so it would seem unlikely that it would be bad, but am seeking advice on whatever anyone else may suggest before I go through the hassle of getting to the pump again.
Does the pump seem likely, or am I missing something?
Forgot to add that when the truck does run, it will sometimes slightly surge a few times before it dies.
Thanks.

Run the codes, what do they say?

On a ‘92? Don’t recall seeing a port for a scanner.

there is a OBD1 port under the hood , but do this instead ( key ON-OFF-ON-OFF-ON within 5 seconds ) and count flashes on the check engine light.

should be a series of flashes , then a pause , then some more flashes

the resulting number is the trouble code(s)

Thanks for the tip. I didn’t think OBD went that far back.

I wouldn't rule out the fuel pump. I had an '88, had a new pump put on, and it crapped out in a few months.

You know those have a frame rail mounted fuel filter don't you? Neglect that and that pump may be bad again.