I had the same problem with my civic, my distributor had gone bad. It wasnt lubricating properly, and eventually it died and I got a new one. There may be a break in one of the vacuum lines or rubber tubes that come off the rochester 2se carburetor or one of the many other vacuum lines. I know-I had my truck shut off and not crank up again due to a dry rotted rubber vacuum line which sometimes are hard to see or find. Have you tried replacing your air filter and breather filter. I was having a problem with my '84 S10. It would not stay running unless you kept your foot on the accelerator, especially in the mornings after it had set for a while. I simply changed these two filters and changed the air temp. sensor, (located inside the breather) and now all is well. It only cost me around $30.00.
Bad fuel? Bad fuel pump? Bad relay?
weak fuel pump.
It needs to stay on all the time the truck is running.
It want stay running
It could be your EGR valve.
Maybe your fuel pump is broke.
Probably a bad relay.
As long as the engine is running, it is normal for the fuel pump to run constantly.
That is normal for fuel injection systems.
lack of fuel
the pump stays running as long as it needs to to keep the pressure up. If you think it should not, check for pressure leaks in the fuel system.
First thing to check / replace is the fuel filter. Next suspect is going to be the fuel pump, and if it is generating sufficient fuel line pressure.