You wouldn't have found an oxygen sensor on a car back before the 1970's. Back then, fuel economy and emissions weren't quite the issues they are today. Things have changed a great deal, and our vehicles have changed as well.

In the old days, an exhaust system was relatively simple. Exhaust gases were collected in the header, or exhaust manifold, and simply exited out the tailpipe by way of the muffler.

Today, the exhaust is a high-tech system that works with the fuel intake system to reduce polluting emissions and improve gas mileage. The Mercury Mystique Oxygen Sensor is part of this system. After exhaust gases have been treated by the catalytic converter, they pass by this oxygen sensor, which literally "senses" the amount of oxygen present. Based on this information, the Mercury Mystique Oxygen Sensor sends data in the form of electronic signals to the fuel injectors. The fuel injectors then adjust the fuel-air mixture for the driving conditions of the moment. Creating an ideal mixture of fuel and air is always a balancing act; cold conditions, heavy acceleration, or ascending hills generally require a richer mixture with more fuel, while normal driving conditions require substantially less. These conditions can change from minute-to-minute. It's a complex set-up, but it allows a modern high-powered six- or eight-cylinder engine to enjoy gas mileage that compares favorably with yesterday's smaller, lower-powered four-banger. When the Mercury Mystique Oxygen Sensor wears out, fuel will not be used as efficiently. Replace yours today - you'll pay the lowest prices on Mercury parts and accessories when you shop with us.We'll meet or beat any competitor's price!