SAN ANTONIO -- The price of gasoline has more people paying attention to what kind of mileage they're getting out of their vehicle.

KSAT 12 consumer reporter Marilyn Moritz conducted an experiment to see if simple vehicle maintenance can help you stretch your dollar.

The test vehicle was a 7-year-old minivan. On the last tank of gas, it got a disappointing 14.8 miles to the gallon.

Marilyn decided to take the vehicle in for some routine maintenance.

The experts at Gus Man Automotive said the first place to look to increase your mileage is the air filter. If you hold the filter in the light and can't see through it, that's not a good sign, because dirt decreases air flow.

"We had dust and all the pollen in the air that's gonna get in there," said Mike Koebke of Gus Man Automotive. He recommended a filter change for the minivan.

Next, the oil change was way overdue. "That's going to decrease your viscosity. So all these things are going to make your engine work harder," Koebke said.

It's also important to maintain the correct tire pressure on your vehicle. Low tires can be a real drag. "It increases friction on the ground, so obviously, it's going to make your fuel economy go down," Koebke said.

So will a new air filter, an oil change and correct tire pressure help with the van's gas mileage? After the routine maintenance, the minivan got 17.7 miles to the gallon. That's an improvement of nearly three miles per gallon; 58 more miles out of each tank of gas. That's a savings of $11.50 per fill-up.

The test didn't take into account differences in driving conditions, like frequent stop and starts and speed, which can burn gasoline quickly.