galant o2 sensor ploblem please help on 2001 Mitsubishi Galant

i have a 2001 galant with the 2.4 i just bought i noticed the o2 sensor was unpluged so i pluged it up and went to leave, i put in gear to go put all the car did was reved up and wouldnt drive in any gear but revearse i unpluged and it was back to normal so idk what to do please help

Asked by for the 2001 Mitsubishi Galant
are you sure it was the o2 sensor?? does not make any sense that it would not allow forward gears.

the check engine light should be on, what are the codes??

im very sure bc its the up stream on top of headers po130 po134,35 the plug was un hooked when i got it the car is in very good shape and runs very good im just a picky person and i wanna get this resolved it just really got me in a pickle bc my experiance with cars i never ran into a problem like this lol