By Steven Nalley
MSU Ag Communications

MISSISSIPPI STATE -- Careful maintenance, efficient driving practices and informed spending can increase a vehicle's fuel efficiency and help drivers deal with gasoline costs near $4 per gallon.

Susan Cosgrove, family resource management area agent with the Mississippi State University Extension Service, said routine tune-ups extend both gas mileage and the life of a car.

“Replace clogged air filters to increase mileage, and keep tires properly inflated to increase it by about 3 percent compared to a slightly underinflated tire,” she said.

Cosgrove said it isn't usually necessary to spend more money on higher fuel grades, as long as the engine is tuned for lower octane. Few automobiles sold today have engines designed to operate in high performance environments under extreme speed, temperature and load conditions.

“Look in your manufacturer's manual to see if you absolutely have to use premium grade fuel,” she said. “If it only says it's recommended, then the lower octane is going to be OK.”

Cosgrove said certain driving methods can increase mileage, such as staying below the speed limit and maintaining a steady pace.

“Don't let your car idle for long periods of time, especially if you're going through a drive-through,” she said. “If you're going to be idling for more than 30 seconds, it's best just to turn the engine off.”

Herb Willcutt, Extension agricultural engineer, said excess cargo such as unnecessary tools or portable fuel tanks can reduce gas mileage. He also suggested carpooling, sharing expenses for hauling supplies and reducing the vehicle's wind resistance.

“Driving without air conditioning would likely increase fuel usage slightly, because lowering the windows would increase wind resistance,” he said. “Camper shells reduce wind resistance for pickup trucks and can result in better mileage.”

Willcutt said the Internet can help save money on gas. Web sites like MotorTrend.com and GasBuddy.com help shoppers find the cheapest gas locally, and MapQuest offers this service along with maps that can point out the shortest and least expensive routes.

“There may be carpooling information on the Internet in larger cities,” he said.

For those buying new vehicles, Willcutt said an automatic transmission may be more efficient than a manual transmission during a road trip. Lower wind resistance and weight make cars more efficient than pickup trucks, and hybrid engines add even more fuel efficiency.fin

“The hybrid systems are designed to recover energy while braking and to even out the energy demands for acceleration and in-town driving,” he said.

While there are ways to save gas and money, some methods people try are ineffective. Cosgrove said fuel added after the pump automatically shuts off can overflow or evaporate, and most gas-saving products such as fuel additives do not actually improve fuel efficiency.

“The Environmental Protection Agency has evaluated more than 100 gas-saving products, and none of them significantly improve gasoline mileage,” she said. “No government agency endorses any of the gas-saving products.”