this may be a silly question but is there fuel in the truck. if there is and your still not firing, the is it getting fuel, is it getting spark, is there enough compression in all your cylinders??
That means it is lacking one of two things. Either spark or fuel. Check each system to see that it works. Insure your fuel pump work, the line has pressure and isn't clogged. The check that you have a spark at the plugs and that they are clean.
It probably has a ignition issue. Check the plugs, distributor/coils, and other ignition components. Make sure the plugs are gapped right and the timing is correct.
there are 3 things that are requred to fire. fuel, spark and compression. check if your cylanders are wet (fuel) check if you have spark in your plugs.
