Sounds like the fuel pressure regulator. When the truck sits for a while (overnight) the pressure slowly bleeds off. Then when you go to start it, it has no fuel pressure so you have to crank it excessively to build fuel pressure then it will start. If you shut off the engine and restart it fairly quickly, it will start fine because the fuel pressure didn't have enough time to bleed off from the regulator.
Its kind of like a slow leak in a tire. As long as you keep filling it with air then its fine. But let it sit for a while and the air will slowly bleed all out. So as long as the fuel pump is running you have fuel pressure. But when you shut off the engine, the regulator is what keeps the fuel lines pressurized. When the regulator goes bad it can't hold pressure anymore and that is what ends up causing hard starts if the truck is parked for a few hours.
