There really is no test for PCMs
Good look at your model here:
http://www.auto-diagnostics.info/ford_eec_iv
PCMs don't usually fail as far as firmware/software, the circuit boards get damaged, so pop the top and have a look inside.
Not sure if you are diagnosing your problems in a good way, or you simply didn't include steps that you did in your explanation.
PCM would be the last stop in a long list of other more common issues.
Main issue on a 1992 would be wiring.
As for fuel do you have power at the inertia switch for 2 seconds when key is turned on, or can you hear the fuel pump come on for those 2 seconds?
Spark on the 4.0l EDIS system is pretty reliable and doesn't need the computer to work, it is a self contained system as far as startup.
Check the Red wire at the coil for 12volts with key on.
EEC relay under the engine fuse box is the main power relay for the engine systems.
When it closes EEC(computer), Fuel injectors, Coil, EDIS module and fuel pump relay get power.
If EEC relay or it's fuse were bad then no fuel or spark would be the result.
