1995 GMC Sierra Stalling problems

Left my pick-up in a company parking lot, and after 2 weeks came back from offshore. Cranked the motor over and it spun but acted like it wasn't firing. After checking the fuel pump found that the fuel pump relay had a burnt coil. Was able to replace, then moved to next problem, no fire on the #1 plug wire after going to ground with a screwdriver. Hauled the truck home on trailer and started by replacing all the ignition components, coil, rotor and module. To no avail confirmed that the distributor was in fact turning, checked timing with #1 TDC on H-Balancer. Everything looked good, checked fire at coil with ignition on and had 12 vdc, checked in cranking position and found nearly 8 vdc. Still no fire, replaced the whole distributor and wahla, it started. But then it wouldn't idle until I removed the wires on the MAP sensor. Plug it back in with the engine idling and it would go dead. Replaced the Map sensor, not any better. Motor would start but wouldn't stay running unless I pumped the gas pedal. So I replaced the in-line fuel filter, no help. Replaced the computer, no help! What Next? I'm about to jerk what little hair I have left, OUT!