Semi-clogged air filters hurt fuel economy for the same reason you don't like to run with a potato in your mouth. The question is, when is your filter dirty? Under a Norman Rockwell schedule of small-town errand running and church duty, an air filter might not see much grit. But grimy city surface streets or just looking at a dirt road on a map are often enough to overwhelm air filters. This one is about conditions. If you go near dirt, the air filter may need changing twice as often as the schedule calls for.
Your maintenance tip courtesy of MSN Autos.
