Also -

Go to post #239 for a video on testing.

Go to post #248 for some corrections to my early post

As far as testing the FICM goes, you have to test the voltage when the engine is cold, and preferabbly when the ambient temps are less than 65*F - like, sitting outside overnight cold. Then, test it Key On Engine Off, during cranking, during cold start running, and during cold running (like, within a minute of the truck starting) at 2,000RPM.