Sometimes they don't throw codes for the O2 sensor per-se, but will come up with stuff like...
"Injector pulse width too low"
Meaning, "Hey this here sensor is telling me it's lean, but somehow I can't seem to hose enough gas in to richen it"
But it sounds like you're not actually in closed loop mode, this could be for several reasons, like the coolant temp sensor being bad, or the MAP/MAF being bad.
I remember The RoadWarrior..To understand who he was, you have to go back to another time..the world was powered by the black fuel & the desert sprouted great cities..Gone now, swept away..two mighty warrior tribes went to war & touched off a blaze which engulfed them all. Without fuel, they were nothing..thundering machines sputtered & stopped..Only those mobile enough to scavenge, brutal enough to pillage would survive. The gangs took over the highways, ready to wage war for a tank of juice