The engine relies on two heated oxygen sensors, found one in each exhaust manifold. Cooling the engine is important before it is removed, as the exhaust manifold, exhaust pipes and catalytic converter become extremely hot during running. To start, take off the negative battery cable and have the vehicle raised to support it safely. Take care to release the electrical connector and don't pull the wire by hand. A Snap-On YA8875 or a crow foot wrench can be used to remove the oxygen sensor. The NGC learns the characteristics of the O2 sensor's heater element, therefore it is important to clear the PCM RAM before installing a new O2 sensor, by either disconnecting the PCM C-1 connector or disconnecting the negative battery cable for a minute. Take out the sensor, then clean the exhaust manifold threads with an 18 mm X 1.5 + 6E tap. Coat the original sensor threads with anti-seize compound like Loctite 771-64, but new sensors already have a coating and don't require more. Adjust the sensor to 41 N.m (30 ft. lbs.), plug the heated oxygen sensor connector back in, lower the vehicle and then reattach the negative battery cable.