Does anybody know a wiring diagram for a 3.0s o2 sensor? And any telltale signs that it's for sure the o2 wired bad, like ways it's running?

 

O2 sensors are not used on cold start, they need to be heated up to above 600degF in order to work, so computer ignores them until engine coolant temp gets above about 130degF, so after about 4 to 5 minutes of running.
Computer also ignores O2 sensors at WOT(wide open throttle), so if gas pedal is to the floor computer ignores O2 and feeds the engine gasoline based on RPM only.

So signs of bad O2 or wiring would be good running when cold but poor running when warmed up, and good power/running at full throttle but poor running when cruising

O2s have 4 wires
2 are use to heat them up faster, heater Circuit, 12volt power and a Ground to computer, computer monitors Ground for heaters to make sure they are working, so you will get "heater code" if this circuit has a problem.

2 wires are for Oxygen content in exhaust, O2s use a chemical reaction to generate their own power on these 2 wires, under 1 volt, .1 to .9volts is the range.
If an O2 sensor part is failing you will get a "slow switching" or Rich/Lean Code

1995 and up 3.0l
Light blue/orange wire is 12volt for heater
heater grounds are, yellow, red/white, and white

Orange wire is the common ground for oxygen sensor
Then grey, red/black, red/green are the computer wires

These are the truck wiring side, O2 sensors have common wiring and 1 to 3 ft leads, so are interchangeable, so wiring at an O2 sensor might have 2 white wires and a grey and black wire

 

would the same wiring work for a 93 or is It different? 3.0

 

Yes, pretty much the same, but 1994 and earlier 3.0l just had the 2 O2 sensors not the 3rd

You test voltages at the computer with key on, for heater circuit and then engine warmed up and running for sensor circuit
Use a sewing needle to pierce the wires to test voltage

Computer wiring diagram here: Ford EEC-IV

Pins 29 and 39 are the two O2 sensors, red/black wire is drivers side(39), Grey/blue is passenger side(29)

Light blue/orange wire is the 12v for heaters