I've been trying to improve my fuel economy by driving more gently, but I'm not seeing the MPG gains I expected. I'm starting to wonder if small things I'm overlooking, like slightly under-inflated tires or using the air conditioning constantly, are having a bigger impact than my driving style. What are the most common 'silent killers' of good gas mileage that people don't think about?
Tire pressure is a huge hidden mpg killer. Keep tires inflated to the pressures listed in the door jamb label and check monthly. Underinflated tires raise rolling resistance and cost you mpg more than you think. Also watch wheel alignment and wear patterns that can sap efficiency.
Air conditioning is a stealth mpg killer especially in summer. Use recirculated air and moderate temps. Open windows at highway speeds creates drag that hurts more than you expect so save the open air for city trips.
Roof racks and heavy cargo on top are easy to overlook. Remove roof racks when not needed and carry only light loads. Every extra bit of aero drag costs mpg on highway runs.
Maintenance keeps the basics from draining your mpg. A dirty air filter can cut mpg by a noticeable amount. Keep the right grade of oil and change it on schedule. Clean fuel injectors and a healthy catalytic converter help.
Gas cap issues can waste fuel through evaporation. A loose cap or a failing EVAP seal costs you mpg until fixed. If the cap is tight and the system light is on have the system checked.
Roof top items add drag and lower mpg especially on highways Remove unnecessary luggage and keep the roof as clean as possible Plan smoother drives and avoid heavy acceleration For more ideas see fuel economy tips 2025