Infomercial some simple tests
Before you spend big money troubleshooting 6.0 running problems here are a few tests you can run.
For suspected injector problems jiggle the wiering harnes near the FICUM if it changes up how it runs something is wrong with the harnesses connections
To check for combustion gases, take the top of the fuel filter and have a helper turn on the key without starting till the fuel is level in the houseing. Turn off the key, unplug the starter wire at the passenger side by the firewall and tough it to the hot post of the battery, with the key off. If you see bubbles form in the fuel bowl you have compression gases leaking past the injectors. This can cause a hard/no start condition.
The best way is of course with a good scan tool, reading the codes and looking at live data readings.
There are several good scanner/readers avaiable for under $400.00
Hope these are of some help.