Driving 55 rather than 65 miles per hour on the highway increases gas milage by as much as 15 percent. Drive at a steady speed, as this is more fuel efficient. Stop and start evenly. Don't idle the engine unnecessarily. Stopping and staring an engine uses less gasoline than letting it idle for 30 seconds, contrary to popular belief.
Less weight means more fuel-efficiency.
Maintain Your Car Don't remove or tamper with pollution controls. Get regular engine tune-ups and maintenance checks. These improve your gas mileage and car performance. Spark plugs are especially important because worn plugs cause poor starting, rough idling, and poor gas mileage. Make sure your tires are properly inflated and that your wheels are aligned.