Properly functioning oxygen sensors are important when it comes to your vehicle's fuel efficiency and reducing harmful exhaust emissions. That's why checking for, and possibly replacing, a worn-out oxygen sensor is an important part of every routine vehicle tune-up. And a routine vehicle tune-up is more than just routine when you use Bosch Oxygen Sensors along with Bosch Spark Plugs as part of a Bosch Premium Tune-Up. You'll be helping the environment and your vehicle's fuel efficiency over the life of the oxygen sensor.