my friend was driving my car up a hill and i guess my fouler kindoff bent down so when he went he scraped the o2 sensor wires clean off.. so being we took it to are friends shop and they orderd me a new downstream o2 sensor from chevy.. they installed it and it runs like **** but if they unplug the o2 sensor car run fine..what could this be??? im taking a guess chevy may have givin the ss/na o2 sensor which could be givin the problem