Check your owner's manual for routine maintenance instructions, and keep the following points in mind:

• Spark plugs must be in good condition. Some will last for 100,000 miles, but many need to be replaced more often.
  
  
• Check the air and fuel filters at least twice a year. Dirty filters increase fuel consumption and can cause poor performance.
  
  
• Inflate tires according to manufacturer recommendations. Under-inflated tires are a safety hazard and can cut fuel economy by as much as 2 percent per pound of pressure below the recommended level.
  
  
• Have your vehicle serviced immediately if the emissions malfunction indicator light— MIL—or "check engine" light comes on.
  
  
• Have your vehicle serviced regularly by a certified technician, who can also inspect important vehicle components that can affect fuel consumption.

At the Pump If your vehicles engine does not need premium fuel, using anything other than regular is simply a waste of money. Other tips include:

• Don't top off your gas tank. In warm weather, fuel expansion can cause overflow.
  
  
• If you must replace a gas cap, make sure it is the right one for your car. A poorly fitting cap can cause engine problems, increase emissions and reduce fuel economy.
  
  
• Keep track of gas mileage. If you notice a decrease in fuel economy, your vehicle may not be operating at peak performance.
  
  
• Look into gas rebate programs such as the AAA Visa® card, which provides a rebate every time you fill up.