If you are noticing poor idling and decreased gas mileage, it may be that your oxygen sensor is worn out. Your sensor should be replaced every 30-60,000 miles as part of your regular maintenance. A defective sensor can be costing you 6 tanks of gas per year! This is a top of the line sensor designed to meet or exceed original equipment specifications. Features include:Designed to meet/exceed manufacturers specifications - identical fit, function and performance Specially designed ceramics to optimize performance and maximize life. Wall thickness and porosity are specifically matched to each make and model.