HOW OXYGEN SENSORS WORK
Every new car, and most cars produced after 1980, has an oxygen sensor positioned in the exhaust. The sensor is part of the emissions control system and feeds data to the Engine Management Computer. The aim of the sensor is to help the engine run as efficiently as possible and also to produce as few emissions as possible. Another reason the engine needs the oxygen sensor is because the amount of oxygen the engine can pull in depends on altitude, air/engine temperature, barometric pressure, load on the engine, etc.
An engine burns fuel in the presence of oxygen. There is a particular ratio of air and fuel that is "perfect" (different fuels have different perfect ratios - the ratio depends on the amount of hydrogen and carbon found in a given amount of fuel).

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If there is less air than this perfect ratio, then there will be fuel left over after combustion. The mixture will be rich. Rich mixtures are bad because the unburned fuel creates pollution. If there is more air than this perfect ratio, then there is excess oxygen. The mixture will be lean. A lean mixture tends to produce more nitrogen-oxide pollutants, and in some cases, it can cause poor performance and even engine damage. Readings are sent from the Oxygen Sensor to the Computer by electronic impulse and fuel/air flow is adjusted accordingly. The use of an incorrect silicone can contaminate the Oxygen Sensor, causing it to send incorrect readings to the Computer. DynaGrip® Silicones are SAFE for use on vehicles with Oxygen Sensors.