The truck has already had the ignition module replaced, He thinks it's either a fuel problem or electrical. Someone told him it could be the computer, and if it is, he was told it would probably start a fire. IF ANYONE has the same prob, or has any clues, please reply.

The truck will ALMOST turn over, and sometimes actually starts, but as soon as you get to a red light, it stalls. There's juice going through the spark plugs, and taking the gas cap off the first time let it start. He thinks maybe a suction problem, (not enough air) but doesn't think that's not the main problem.

Also, I need to know what years of computers are compatable with the '87 4x4 F150. It's a manual with a replaced straight6 engine.
Thank you in advance.

Check the fuel filter for proper flow and the fuel pressure at the rail if it is fuel injected.

If it has a carb make sure it is tight. Tight to the manifold and tight itself.