The Mercury Sable Oxygen Sensor is an integrated part of your car's exhaust system. Its purpose is to work with the fuel injectors to insure that every drop of precious fuel is being used as efficiently as possible. Your engine uses a mixture of fuel and air in order to run.

The ratio of fuel to air in this mixture needs to be adjustable for different conditions. For example, when an engine is cold, or running under a heavy load, it needs a mixture that is "richer" in fuel.

For ordinary driving conditions - temperate conditions over level terrain - the mixture can be "leaner," containing more air. These conditions can sometimes change from one minute to the next. In the old days, this function was controlled by the choke knob. By cutting off the air supply, the driver could literally "choke" the engine, causing it to run a little richer and idle faster. It was not a very efficient method of fuel mixture control. The Mercury Sable Oxygen Sensor does this by analyzing exhaust gases exiting from the catalytic converter for oxygen content. Based on this information, it sends electronic signals to the fuel injection system to adjust the fuel mixture for the driving conditions of the moment. The result is that fuel is burned more completely, reducing consumption and emissions. Since the Mercury Sable Oxygen Sensor is located underneath the car, it can take a real beating along with the rest of the exhaust system. When gas mileage starts to fall and everything else about the engine and fuel system checks out, a faulty oxygen sensor may be to blame.Get the best deal on all Mercury parts, right here!