well, my car has been missing for a while and i have noticed my gas consumption has gone up slightly...and im also getting a code for the upstream o2 sensor. i also took out my plugs and they were pretty black...also indicating a rich condition. well today i ended up unplugging the sensor after the car was fully warmed up and nothing changed, it kept right on going. now i know the load is shifted between the o2 sensor and the map sensor, but i forget when each takes over. anyways...since nothing changed when i unplugged it, is it a pretty safe bet to say its shot and i need a new one? oh and where can you get an o2 sensor socket? are all the sizes the same? i want to BUY one, not rent one..plus i dont have an autozone around me. tia!