92 Explorer 12 mpg

Any body take a stab at these EOKO codes 522 clutch Neutral position
565 Canister purge selonid system KOER 171 O2 sensor switching, at adaptive limit 173 O2 sensor not switching system was rich then reset codes EOKO 565 171 173 KOER 179 Fuel was rich @ part throttle 528 171 173 . Alots been done to engine trying to trouble shoot low fuel economy with check eng light part time. Mass Air Flow was R/R with rebuilt one and O2 sensor been R/R with Bosh type twice. Fuel injectors cleaned but might need additional clean.Fuel Filter was changed, filter was dirty previous Air filter is good.. Runs good just rich I have another Canister selonid from salvage but havent done anything with it until I obtain more knowledge. Thanx David

The adaptive limit is thing means that the controller cannot lean the system out enouh, ie - always too rich....
sounds like a fuel injector or two is stuck open.

There is one way to test, put a fuel pressure test gauge on the test port on the fuel rail, run the engine , shut it off and see if the system holds pressure. Unfortunately this will also show if the regulator leaks down or the fuel pump check valves leak back so it is not a 100% test for a leaking injector, but given your symptom, it is very likely.

If you haven't found your way to ford-trucks.com, do so.
They are some of the best ford guru's I've seen; F150 myself

Cheers,
Popa Tim