Computer controlled engines aren't a Ford thing.
TFI and Pulse Vacuum Hubs are Ford things, bad things, lol.
Plugs, wires and fuel filter are normal long term swaps.
Like air cleaner and oil, oil filter are short term swaps.
Replacing sensors is generally a waste of money, volt/ohm meter will test pretty much any sensor or control.
Tighten lower intake manifold, they loosen up on 4.0ls
What kind of mileage on the truck?
O2 sensors are good for about 100-150k, you will notice slight drop in MPG as they start to wear out, O2s tend to fail "rich", then replace them both(Bank 1 and Bank 2)
You will save the cost of the O2s on the MPG increase over the next year, lol.
Don't forget to unhook battery during, or after, cleaning or changing ANYTHING on a computer controlled engine, this reset computer so it will relearn parameters.
Some 4.0ls had EGR system, does yours?
I would invest $25 in a vacuum gauge, works on all gas engines, then run the tests.
Read here: Technical Articles: Engine testing with a Vacuum Gauge - at Greg's Engine & Machine
Where you see "carb" think fuel injector, for "points" think coil.
An engine is still an engine no matter how many extra parts you add, lol.
The electronics actually make things more reliable, not harder to work on.
Your '94 only uses the computer for fuel, spark is done by the EDIS-6 module on the rad support, it sends pulses to computer(PCM) to synchronize injectors and does get spark advance updates from computer, but the EDIS can run spark all on it's own.