FF sensor wires
Black = Ground
Light Blue/Orange = 12volt from Fuse 13, 15amp
Dark green/light green = pin34 on PCM, signal wire to computer
If you have a scanner, then with engine running you should be able to select FF sensor and with regular gas FF sensor should be showing 40-60Hz.
Engine should idle at 1,000-1,200rpms when cold
It should drop down to 800 with automatic, 700 with manual when warmed up.
After it is warmed up and idle is still high, unplug IAC(idle air control) valve, idle should drop to 500 or engine may even stall, either is good it means no vacuum leak, but also means computer is running idle high for some reason.
If idle stays high then you have a vacuum leak.
What isn't working on the 4x4 part.
No dash lights
no sound from transfer case shift motor
No front wheel engagement
2000 was the last year of the PVH(pulse vacuum hub) 4WD system, but not all 2000's had this, Ford was phasing it out, for good reason.