Recent threads similar to this have focused more on running out of gas. Bad gas, crud in the tank, or an old filter. Since you've replaced all that, perhaps it could possibly be a pinhole leak in the fuel pump diaphram, or a non-vented gas cap was installed. The cap must be the vented type or the resulting vacuum in the tank with cut off the flow of fuel to the pump.
Is it known if the truck ran okay when parked? If it's been sitting for a long time the lifters could be gummy or stuck providing inaccurate clearance, or the points or timing may be off enough to cause a problem. You might also check to make sure the exhaust isn't clogged with a frozen heat valve or a smashed tailpipe. An open vacuum port somewhere that got missed can cause a hard to diagnosis condition. If you can keep it running long enough to get a reading with a vacuum gauge, that might provide a wealth of information.
I wouldn't think it's the coil, since they usually either work, or don't. If it is electrical, I'd check to make sure the ignition switch and starter terminals are tight, and the battery cables are securely tightened to the starter and engine block.
