But the point was it would have to be incredibly dirty to make a noticeable difference in either gas mileage or performance.KdudL said:If you have a dirty stock filter it will lower gas mileage aswell as performance, but if you have a cone filter I wouldn't worry to much!
UnderDog said:If you have a stock filter, take it out and flip it around 180 degrees every time you change your oil until it's time to change it. You can see if you look at it at just the right angle where all the dirt collects. Flipping it around makes the air hit a cleaner part of the filter. It's like flipping over to the cool side of the pillow. When you're doing that, give it a few good slams against the ground to get all the big debris out.