Oxygen Sensor Plug (85-21686) by K&N®.
A computer controlled electronic fuel injection system uses an oxygen sensor to signal the computer the status of the air / fuel mixture. The sensor samples the oxygen level in the exhaust and sends this information to the computer. The computer then recalibrates the fuel delivery system, thousands of times per second, to maintain the proper air/fuel ratio throughout the entire rpm range.
The same technology is used in the K&N Air / Fuel Ratio Monitor. An oxygen sensor measures the amount of oxygen in the exhaust gas and illuminates a group of LED lights indicating the actual air/fuel mixture: lean, rich or just right. Using the K&N Monitor, you can adjust the mixture for peak performance, economy or drivability. It can also be used to prepare a vehicle for emissions testing or as a piece of dynamometer test equipment. An oxygen sensor can also be installed in both exhaust pipes of a V-type engine to check fuel distribution. The Monitor can then check either bank with the flip of a switch (switch not included).
Note: The K&N Air / Fuel Ratio Monitor is not compatible with leaded gasoline, nitromethane or diesel fuel.
K&N® is the inventor and leading innovator of reusable cotton gauze filter technology for automotive applications. The first K&N filter was conceived for racing over 40 years ago and a performance enthusiast mindset continues today throughout all levels of the company. K&N is the sales and brand leader for performance filters, including an extensive line of factory replacement filters and performance air intake kits. The company actively promotes the environmental, economical and performance advantages of long-life reusable cotton gauze filters.