yep you can check and clean out the mixer and also clean the chamber in the vaporizer as well, most vaporizers have a plug you can remove and if anything is in there you can drain it out.

one other thing that comes to mind is if this truck has a start timer on it like some other trucks i've seen with the vortec engine. The timer allows the engine to spin up and then turn on the ignition, it helps keep the starter from mis-enguaging and also helps the ignition during startup. The symptoms they usually give is either a 'no start' or you can get a 'misfire' during starting.

check and see if it has one of those modules on it.