If you can benefit from all the tips in this article, you have the potential to save a whopping 30 or $.07 a gallon. Underinflated tires create more resistance and drag, causing the engine to work harder and use more gas.

Here are nine proven ways to improve mileage by preparing and maintaining your car, truck or van. Recommended maintenance should be done at the correct time intervals, so the vehicle is always running at its best efficiency. This will naturally give you the best gas mileage.

1- Check your tire pressure every three weeks in all four tires. Invest in a good quality pressure gauge. Tires have a recommended inflation range (eg 32 to 35 psi). Your tires should be inflated to the higher number of pounds, recommended by the manufacturer. This will give you the best mileage. Studies have found that if your tires are only 5 pounds underinflated, you will lose 2% or $.07 a gallon. Underinflated tires create more resistance and drag, causing the engine to work harder and use more gas.

2- The engine uses gas to transport every pound in your vehicle. The more weight, the more the load on the engine and the more gas is needed every mile. Take out as much excess weight as possible. We all have "stuff" in the car, like golf clubs, that doesn’t have to be there all the time. The U.S. Dept of Energy estimates that we can save 2 or $.70/gallon. Using high performance spark plugs will yield the best mileage.

6- Remove your roof rack if it is not being used, because it causes extra wind drag and reduces your fuel economy.

7- Lowering a tailgate on your pickup will give it less resistance to the wind and improve your mileage.

8- Synthetic oil can save an average of 5% or $.14 a gallon. It lasts longer than regular oil and allows your engine to work more efficiently. Once you change to synthetic you must keep using it. Synthetic cannot be mixed with regular, so it is a good idea to keep some with you if you need to add a small makeup amount. Usually, brands cannot be mixed.

9- The next time you need new tires, consider the latest high mileage designs. Goodyear’s fuel-saving tread compound provides a low rolling resistance. The manufacturer says that this can save up to 2,600 miles worth of gas over the life of the tires (60,000 miles). Figuring gas at $3.80/gallon and an average of 18mpg before switching, there would be a $527 saving over the life of the tires. This is almost enough to pay for the tires.