having troubles with no start issues, fuel related I think. Engine will spin over, lp has good pressure but won't fire. Usually have to spin over for roughly 30 seconds before it cranks. BUT, can drive around, kill the engine and will fire right up again. If it sits for more than 3 hours or so it won't crank right up again. Runs fine after starting.
Have checked: fuel pressure, for fuel leaks, filter, swapped out Lp, opened inj lines while running to make sure no air in lines.
Does the 24v have fuel shut-off selonoid like the 12v? truck has been doing this for 4 days now. Wouldn't think its the IP because it starts right up at times.

 

Noticed that when parked on an incline, back end lower than front, truck has trouble starting. Parking with front end lower, no problem with startup, even after several hours (tried this several times). Could the pump loose its prime and cause a fuel delivery issue?

 

Your symtoms can be caused by a leaky fuel line that is letting air get in the system. Go over your fuel lines looking for a wet spot. Might not find one, but could still be a bad fuel line or fitting.