My dad has had this problem for a long time and I figured I'd ask you guys what could be the problem. When he tries to crank his truck, it takes it a few seconds to finally start. (5-10 seconds)

What causes this?

 

The first thing i would do is check the fuel lines/fuel pump/injectors. I would also check your cam positioning sensor. It could also be a fault in the electrical system somewhere.

 

Try this, turn the key on until all the dash lights turn on but not start the truck, wait about ten seconds (give the fuel pump a chance to fill the lines with fuel) -then start the truck . If it starts fine then the fuel line is not holding fuel pressure, these trucks fuel system is under constant pressure. The fuel presure regulator is mounted on top of the fuel pump, which is located inside the gas tank.

hope this helps

 

Actually somebody told me to try that before, xyzik. That didn't help it.

 

maybe a bad/ worn out crankshaft position sensor?

 

turn the key to the on position untill the fuel pump stops whirring. turn it off and back to the on position untill the pump stops again. try starting it then. i dont think that the pump keeps pumping continuously untill the truck is actually running.by turning it to the on position a few times the pump will finally get the gas to the rails. that's what's happening to my truck right now.