A fuel pressure gauge and a scan tool that can read live data would be real assets here, and should be considered mandatory equipment if you plan to diagnose and troubleshoot EFI. As suggested, you need to check cranking fuel pressure. The injectors poppets require a minimum pressure (around 30psi, I think) to fire, so you will get no start until that much pressure builds in the fuel system. Cranking the truck while watching a fuel pressure gauge will tell you if the system is having trouble priming. One way to check this without a gauge is to turn the key on and allow the fuel pump to run for several seconds before trying to start the truck. If it cranks immediately after being given a chance to prime, then you have fuel system leakoff through the pump, one or more poppets, or the regulator. You can test the pump by running the pump with the line deadheaded to a gauge, and then recording how long it takes for the pressure to drop off after the pump stops running. The injectors and fpr can be checked by removing the upper intake, pulling the injectors out of their ports, and then cycling the key on to pressurize the system. If the FPR or any poppets drip fuel, then you have found a leak path. Dirty poppets can sometimes be cured with judicious application of fuel system cleaner, like techron. If the regulator is leaking back to tank, then it can only be replaced.
Going back to the scanner, you can also watch IAC steps and make sure that it is being commanded to open during startup, and pulling the IAC valve and cleaning it and the passage doesn't hurt. Looking at all sensor data like intake air temp, coolant temp, throttle position, and manifold pressure may also point to a problem. If the coolant and intake temp aren't within a couple of degrees of each other with the truck dead cold, then one of the sensors is suspect and could cause a problem. Manifold pressure should be atmospheric pressure with the engine off. Throttle position should be zero. Things like this are important to check before digging too far into a bigger mechanical issue.