Do high performance air filters increase fuel mileage?
Air filters do not increase fuel mileage. Even a badly clogged filter will not lower mileage. As the air flow is decreased the fuel that is added is also decreased and mileage will remain constant. This is not to say filters should not be changed. A dirty or clogged filter will affect performance and may get sucked into the air box, allowing unfiltered air to enter the engine. A more detailed article on increasing fuel mileage is in our Detailed Auto Topics section under Saving Gasoline, Saving Money.
