You didn't mention this thread (link below) and the low oil pressure ............
http://powerstrokearmy.com/forums/showthread.php?p=1438934#post1438934
Did you resolve it?
You didn't post a resolution.
You have good suggestions here and no response - whats up with that?
Get knowledgeable and take care of the truck (excursion) or find a good mechanic.
Getting knowledgeable will require a way to read engine parameters / codes as mentioned above. Then you will have to read a lot and post up a lot of data.
A complicated machine can not get fixed over the internet without information and communication.
Tests to run in order to begin troubleshooting:
First - scan and record ALL codes (DTCs). Make sure batteries have been fully charged and individually load tested. Low system voltages can sometimes cause some interesting problems. Verify proper oil level (and oil appearance) and that you have sufficient fuel. You may want to even change out the fuel filters so you can inspect them (sometimes you can get bad fuel). Your oil and fuel filters MUST be Motorcraft and the filter caps must be the Motorcraft OEM ones. wrong filters or mismatched filters and caps can cause a range of problems - some small, some big.
If you haven't resolved the low pressure suspicion in the low pressure oil area, resolve that first. Put a mechanical gauge on the system (we can show you where), and/or inspect the low pressure regulator (by the harmonic balancer)
Do the things below when the engine is cold and not starting.
1. Verify ALL injectors are buzzing (KOEO). During the test, all injectors will buzz for 2 seconds. Then each injector will buzz sequentially for 1 second.
2. Verify cam/crank sync and FICM sync when cranking. Both sync values should be "1".
3. Determine system voltage (battery power) while cranking, System voltage should not drop below 10 volts when cranking (10.5 to 11 volts is normal).
"4. Determine rpm when cranking. Rpm must be 150 or above to start. No rpm signal and no SYNC when cranking typically points to the CKP sensor.
If cranking rpm's are low, make sure an accessory (A/C compressor or pulley) isn't seizing up and causing the slow spin."
5. Determine FICM Power (MPower, VPower, LPower). Mpower should NEVER drop below 45 volts (47.5v cranking is normal). Lpower should be above 9 volts when cranking (below 8 v and engine will not start), and Lpower should typically be 11.5 - 12 volts. Vpower should be the same as battery power.
6. Determine Fuel Pulse Width while cranking. If no fuel pulse width signal is received, but rpm, Vpower, and ICP signals are normal, then the CMP sensor is in question. Typical FPW when cranking is 500 μ seconds or greater, up to 2 milli seconds (990 usec low idle and 680 usec high idle)
7. ICP pressure, ICP voltage, and IPR % duty cycle when cranking. ICP pressure should be above 500 psig (preferably 650 minimum); volts should be .9 to 1.2
8. Determine V-reference voltage. Voltage should be between 4.5 and 5 volts.
9. Verify (manual gauge required) fuel pressure is 45 psig minimum
10. Verify that the upper fuel fuel filter fills in several seconds KOEO.
11. If low ICP pressure, verify oil filter housing fills up when cranking (in several seconds when holding the drain valve closed, 10-12 seconds w/ drain valve open)
http://www.nosun.ca/wingnut/051207.PDF
12. Run a fuel bubble test (see detailed instructions). Bubbles from the stand pipe indicate air from the pump. Bubbles from the side indicate an injector problem.
13. Disconnecting various sensors & components one-at-a-time can often times prove valuable (EGR, EBP, ICP, EOT, ECT, BARO, GPCM, MAF)
14. Verify that MAP, BARO, and EBP are within 0.5 psi of each other with KOEO (within 3% of each other)
15. Verify that IAT1, IAT2, TFT, EOT, and ECT temperatures are all relatively close after at least 24 hours with the vehicle off (cold soak).
As mentioned above, getting your FICM tested is a good idea. I would recommend FICMrepair.com. But first, test the voltage when cranking (again - cold engine), AND READ/POST THE CODES! Even pulling the EGR valve (if it is still there) would be a good idea (check for a stuck open valve, and also check for water in the intake).
Checking the glow plugs is also a good idea. We can post more on that later. Do you have a way to ohm (check the resistance) the glow plugs? How about having access to an inductive ammeter?