Nearly one in five cars on the road has a loose gas cap. The Car Council says an unsealed cap allows gasoline to evaporate. It can reduce your mileage by up to two miles per gallon.
That's as much loss as you would have with gas wasters such as underinflated tires, dirty air filters and worn spark plugs.
Always twist the gas cap until you hear it click. On older vehicles, check for a tight seal. It pays to buy a new gas cap.
Driving 55 miles per hour saves gas, but as long as you keep speed at 65 or under, you'll save fuel on a trip, according to Edmunds.com.
On dry roads, use cruise control to keep speed steady.
On frozen roads, cruise control is not the best idea. You'll want to speed up and slow down as conditions and traffic allow.