I've heard that maintaining your car tires improves gas mileage. Is it really true? --Daryl B., Allen, TX

Improperly inflated tires require more energy to maintain speed, which burns gas. Blow those wheels up right and you can improve your mileage by around 3% compared with underinflated tires. “Check the sticker on your car’s doorjamb and it’ll tell you what pressure to use on your tires,” says Tony Quiroga, senior editor at Car & Driver magazine.

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