The O2's are the feedback mechanism for the air-fuel trim. Generally but not always, an aero fox will run rich in FMEM, such as you are. This is not always the case however.
How badly do you want to fix the car? It seems like you would rather argue than take the advice offered.
Diagrams courtesy of Tmoss & Stang&2birds
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 86-95 5.0 Mustang wiring Mustang FAQ - Engine Information Everyone should bookmark this site.
Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.
If you need some help with your automotive electrical skills, try Automotive Online Instruction for a beginning course. The course is very good and best of all, it is FREE!!!