Old vehicles gulp gas
Myth: Fuel economy decreases significantly as a vehicle ages.
Despite this common misconception, gas mileage generally continues to improve over the first several years of ownership during the break-in period -- about the first 5,000 miles, according to FuelEconomy.gov.
"Barring normal wear of internal engine parts at very high mileage, there is no reason why a properly maintained engine won't deliver the same fuel economy over its operating life," says Tony Molla, spokesman for the National Institute for Automotive Service Excellence in Leesburg, Va.
The key phrase there is "properly maintained engine."
Regular maintenance will keep your engine running at peak efficiency, Molla says. That means you should replace parts such as spark plugs before problems occur, he says.
How to save: "Regular maintenance is the best investment you can make to keep your vehicle running efficiently and reliably over the long term," Molla says. And fixing serious problems such as a faulty oxygen sensor can improve your mileage by as much as 40 percent, according to FuelEconomy.gov.