Please check fitment notes & description for accurate information. 1997-1999 Audi A8 3.7L 1997-1999 Audi A8 Quattro 4.2L Oxygen Sensor's Location: How do I know the O2 sensor is good or not? Check engine light on A reduction in fuel economy. Your catalytic converter fails unexpectedly Exhaust emissions reach undesirable levels. How to install the oxygen sensor? .
