Hi all. My check engine light is on and I get code P0171 (Autozone) which means car is running too lean. The cat I purchased the car from said it is the first oxygen sensor on bank one. On top between the motor and the firewall and is attached to the header. Is that english? Is this something that I can pop the hood and see? I wanna at least try to fix it myself. Or should I just go buy the sensor ($100) and take it to a mechanic ($70)?