Replacing a faulty oxygen sensor (also called O2 sensor) can save a lot of gas.

The United States Department of Energy - Fuel Economy Tips page states that replacing a faulty oxygen sensor can increase efficiency by as much as 40%, producing an equivalent savings of $1.00 a gallon.

If you have experienced fuel injector problems, oil burning, or loss of antifreeze into the combustion cylinder, there is a good chance that your oxygen sensor has become fouled and needs replacing.



Oxygen sensors can also become weak or less effective over time. Though they may still function, they will become less effective at maintaining peak air/fuel mixture. When that happens fuel economy will suffer, sometimes greatly.

Your car’s oxygen sensor location is in the exhaust pipe ahead of the catalytic converter. A lot of newer cars have more than one oxygen sensor. How it works is by sensing changes in oxygen levels in the exhaust flow and sending this information to your car’s computer. The computer uses that information and more to electronically control fuel injectors to maintain a correct fuel air mixture.

How often you should change your oxygen sensor under normal wear conditions depends on the model year of your car and type of oxygen sensor.


Oxygen sensor information:

The Autotap Preventive Maintenance Page includes details on replacing oxygen sensors.

How Stuff Works Oxygen Sensor Pages are a good resource and include links to oxygen sensor test procedures.

The Wikipedia Oxygen Sensor page is loaded with technical details of operation.


You can purchase oxygen sensors online at Amazon Oxygen Sensors, , and .

You can also check price and availability of O2 sensors at local auto parts stores.

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