Check the Date on the Door Jamb Label provided by FORD. If it's later than AUG/SEP 1992 it's a 1993 chassis. Could make a difference in troubleshooting and parts.
According to RockAuto.com a 1992 has O2 sensors. Or SensoR. It only shows an Upstream (of the Converter) sensor. Some three-wire and some four-wire. That would mean it has some form of fuel mixture control.
Is this 460 TBI (Throttle Body Injection, Two Injectors in a carburetor-looking body) or MPI (Multi Port, Eight Injectors)?
Injectors are pretty dependable. This is above my pay grade, but I wonder if a clogged injector would not be detected as a fault, but run that area lean. And maybe even the O2 sensor report lean and richen via the rest of the injectors.
