ruck won't stay cranked

Get any codes from the computer, very important. Check to see if the power to your coil packs and injectors ( red wire ) is still there with the key on. I ask this because if you have a defective ignition switch, it will crank and run then die as soon as you let go of the key and the ignition switch goes to run. Something to think about.

have you recently changed the fuel pump? if NOT, you could possibly have a dirty fuel pump screen. i say this bcuz it can stay on just long enuff to get the 40lbs of pressure, but when it can no longer get gas through the screen it will shutdown. when you check the fuel pressure does the gauge bounce or stay steady at 40 lbs? this is another thing that may lead to dirty f/p screen. also make sure wires are in correct firing order. if all this is in order and you do not have dirty f/p screen, scan vehicle and get codes to give you a better idea. they have code manuals at Oreilly auto parts its a chiltons manual i believe...email me if i can be of further assistance charlyboy_979@yahoo.com