Starts and Dies all day long

[editedpoo]

2003 F350 Crew Cab 6.0 4x4 Automatic. I was on my way to work the other morning, was about 5 miles from my house when i noticed the Tow/haul light on the gear shifter was flashing. Turned around to take the truck home, got up to 55 mph and the truck died. Pulled over and restarted fine, that light was still flashing but i was able to drive it home. Parked it and was letting it idle for a minute to cool down and it died again. Restarted again, idled for about 30 seconds and died. Pulled the EGR valve and cleaned it up real good but still same issue. Tested FICM this morning and has 48 volts from start to idle to 2500 rpms. Any input on where to look next? Fuel filters were replaced about 500 miles ago along with oil and air filter. And any thought on the transmission flashing? Can anyone tell me how to test the fuel pressure? I think I need to try that but I cant figure out exactly how..

[Acidsniper]

Are you able to pull codes (both hard and soft codes)? Could be your HPOP related but given the flashing of the tow/haul light so erratically and unexpected it sounds more like an electrical issue which has me leaning towards the PCM as the possible source.

Other things worth checking:
Remove oil cap, does it fill when cranking?
Remove secondary fuel cap, does it fill when cranking?
Are you getting any smoke at all?
When you tested the FICM did you test 1. Key on engine off 2. Cranking 3. Idle?
Did the tranny go into "limp" mode after the tow/haul light started flashing?
What's your voltage at the batteries and alternator?

A common problem that can cause the tow/haul mode light to flash is a faulty / broken trans temp sensor causing the truck to think the tranny is overheated which causes the truck to go into "limp" mode

[editedpoo]

i am not able to pull codes, the truck wont stay running long enough to get anywhere with a code reader. i am looking at buying one, but dont know what kind that will pull both CEL codes and the hidden ford codes. any thoughts on which one?

ficm tested 48v through KOEO, crank, idle, and up to 2500 rpms.
no noticable smoke, even on a cold start after the truck sat for 2 days untouched.
good fuel pressure at secondary filter, 48~ psi.
i am ordering a new TFT sensor, i noticed this morning that within 20 seconds of idling the trans temp was about half way up the gauge. checked and have good fluid level, so im thinking the sensor is faulty. also going to get a new trans filter and pan gasket and do them at the same time. is the external trans filter a dealer only part or can i get it at any parts store too?