Order a new Plymouth oxygen sensor from our site, and be assured you are purchasing a quality instrument that can endure high heat pressure and constant usage. Oxygen sensors should last up to 100,000 miles, although some factors can shorten their lifespan. If an oxygen sensor is coated with a fluid leaking from the engine, such as oil or coolant, the sensor's voltage will be hindered. If you accidentally use leaded gasoline in an unleaded fuel system, or a gasket sealant that is not sensor-friendly, the oxygen sensor might fail. In addition, sensors need to be extremely hot - about 600 degrees Fahrenheit in some models - to be activated. When the sensor is unheated, it acts as a resistor in a circuit between the sensor and the Electronic Control Unit. When it is heated, it acts as a battery, as the layers inside generate a current that is passed on to the ECU, informing it about the levels of oxygen in the exhaust. A ceramic exterior shields the inner parts from the heat, but eventually the heat will wear out the exterior and interior layers. When it wears out, you will notice that the exhaust is running too rich (too much fuel is being added to the combustion) or too lean (too little fuel). That is the result of the ECU not receiving proper data from the oxygen sensor; instead it must rely on other sensors in the engine to guide how much fuel to add through the fuel injectors.