O.K. Bernie you say it cranks & tries to run //// you have plenty of power in the battery not a cable issue but what I needed to know is does it happen then start again and then you drive a little bit and it happens again then you wait 20 minutes and it starts again or are you stuck with a lot of cranking power from the battery but no start and then later it will start again /////// there are a lot of things that could be happening so you must bare with me here I'm not at the vehicle first what is the condition of the ignition wires(do you have regular spark plug wires or a 4.0/4.6 with coil on plug boots)if it's regular wires they may be old and leaking voltage and will cause the no start especially if it has rained or is raining at the time because the +voltage leak is able to jump/arc to the engine - ground instead of firing the plugs ==no start next are the spark plugs new/old in gap if they are (a) out of gap to much air space for the + voltage to make contact with the bottom electrode so when the truck starts and runs it's barely making it but as the engine gets hotter fuel is vaporizing fast and the spark plug is not producing the voltage to cause the fuel combustion explosion that happens in the cylinder for each plug because they are out of gap they'll fire up a cold motor but not a hot one /////stay with me Bernie there's a lot to explain here next/// do you have coil on plug with spark plug boots yes/no //if yes you must take each one out & inspect them for (a) very soft (b) cracks in the boot ////check by flexing the boot back N forth to see the strength of the boot should be stiff if they are very soft there's probably a leak in it even a pin hole will cause problems with leaking voltage also squeeze the ends of the boots multiple times to see if there are cracks in the part where the spark plug fits into it below you will see the wires & boot with the contact for the coil the spring you see if this is your system of coil on plug you must after taking the boots off pull out the spring and look into each coils hole at the contact it will look like a blade that the spring fits over if it is green or has a powdery coating clean it using brake parts cleaner or alcohol & emery boards that the ladies use for there nails trim it down and get that blade contact shiny also check the base of the coil on both sides === plug side from electrical system coil connector/spark plug side for cracks marked below with ^^^/>>/<</// if this kind below check the coil towers>>>>>> for cracks on the coil and the actual wire you plug in
the red here ^^^^^^^^^^^^ and the connector you plug in look inside for breaks in the connector
<<< also cracks in the plug or wet spark plug boots
<<<<<<<same thing here and here^^^^^
^^^^^^^--------------^^^^^^^ once you have done all checks of the ignition components check the coil for voltage with a meter if there are wet boots from oil antifreeze or just water for antifreeze could be cracked head (the worst thing ) but most likely a leaking manifold/thermostat gasket is letting it in ----if its oil you'll find it in the rear cylinders 4/8 or front 1/5 on the 4.6 if it's in others may be rings or valve seals ---- water the splash shields on the fenders are missing and the carwash or heavy rain is letting the water into the spark plug chambers there is much more here to// change the gas filter and see what happens a lot of dirt could have gotten in your tank from a dirty fill up and if the truck starts to run a little longer but it happens again there's a lot of dirt in the tank and the screen on the fuel pump is getting clogged^^^^^ below and when the fuel settles so does the dirt & the truck starts again because the gas can get through now till it gets mixed up again & clogs the screen so let the gas go to almost empty & take out the pump & look at the screen you can clean it but chances are the pump is going to go anyway because the gas is what cools it off as it flows through but repeated cranking with no fuel going through will make it over heat & repeatedly doing this shortens the pump life & on a 12 year old vehicle this came out in 03 for 04 it's probably almost done so if you find this condition drop the tank clean it out with water and quickly wipe the inside down with rags then spray carb/fuel injector cleaner a whole can make sure you spray all the seams we don't want water left behind at all it will rust out the tank and let air dry after wiping with clean rags then pop in a new pump fill with gas & just turn the key to the on position so the pump can build up pressure then crank for starting
^^^^^^^^^^^^^^ that's it so do these things and post back with progress report and we will continue till I get you there as you can see here I've done a lot of work for you and I will continue if the problem persists I'm going out with the wife now & will look for your post hey Stephen it's Bernie LATER MAN!