Truck Cranks but won't turn over. Already replaced : starter, distributer cap and rotor, icm, coil, coil plug, spark plug wires, and spark plugs. Still won't start
This suggests you may have a fuel supply issue if you have confirmed that you do have spark. Try pulling one of the spark plugs out after cranking it to see if it is wet with fuel. If it is wet, this means you are getting fuel to the cylinders. If it is not wet, this suggests you have a fuel supply problem that may be related to either fuel injectors or potentially a fuel pump problem.
I would also suggest testing the fuel pump first by just turning the key on and listening. You should hear the fuel pump come on as it makes a fairly noticeable light buzzing sound. If you do not hear this, I would recommend checking the fuel pump fuse as well in the fuse box. If this fuse is burnt, this can cause a lack of power to the fuel pump as well. If you need help pinpointing the problem, I would suggest having an expert from YourMechanic come to your home to diagnose the hard start and assist with repair.