A faulty oxygen sensor can rob your 2002 Nissan Altima of performance and gas mileage. If your oxygen sensor reads high it will ask your car's on-board computer to make the oxygen-fuel mixture more lean. This can cause your car to misfire, idle poorly, and hesitate. Over time this can lead to catalytic converter failure. You can replace you Nissan's oxygen sensors yourself to save yourself some money. This is a simple auto repair that you can do yourself in under an hour.
Run a OBD2 test on your car to determine which Oxygen sensor needs replacing. This can be done by connecting a OBD2 reader to the connector located under the steering wheel column. Your 2002 Nissan Altima has four oxygen sensors two located near the exhaust manifold and two near the catalytic converter.
Disconnect the black, negative battery cable. Use a jack to lift the car, then place car onto jack stands to keep it secure while you are working underneath.
Disconnect the oxygen sensor's electrical connector from the car.
Use a crescent wrench to unbolt the oxygen sensor from the exhaust pipe. You can use an oxygen sensor socket if your oxygen sensor is difficult to reach.
Use your crescent wrench to bolt on your new oxygen sensor. Tighten until the sensor is snug into place, do not over-tighten. Clip the oxygen sensor's electrical connector to the cars electrical adapter.
Lower the car and reconnect the negative battery cable.
