Savvy Consumer: How to Ease Pain at the Pump

March 30, 2007 — -- If the weather makes you want to go for a nice spring drive, but pricey gasoline makes you want to stay home, there are some modest adjustments you can make to save money. After all, we are a car culture.

The amount we spend on gasoline over our lifetimes is ludicrous. And we don't have to burn so much or spend so much.

AAA says only 5 percent of the cars sold in the United States require premium gasoline. But premium accounts for 20 percent of all gasoline sold. What a waste. Say you use 20 gallons of gas per week. Regular costs an average of 20 cents less per gallon, so you'll save $4 per week -- $208 per year!

Using a higher-octane gas than the manufacturer recommends offers no benefit at all. But people remain convinced that premium gas will make their cars go faster or get better mileage. It's just not true. All the term "octane" refers to is a fuel's ability to help your car resist engine "knock." This knocking, rattling or pinging sound comes from premature ignition of fuel in your engine.

Your car is built to run on whatever grade of gasoline is recommended in your owner's manual. If the manual says premium is "required," use it. If it says premium is just "recommended," ask your mechanic if you can experiment with regular or mid-grade.

But the vast majority of cars are designed to run on regular octane. The only reason you would need to switch to a higher octane is in the rare instance that your engine might be knocking when you use the recommended fuel. Light knocking is not harmful to your car, but heavy, persistent knocking can cause engine damage.

Most gas stations offer regular (usually 87 octane), mid-grade (usually 89 octane) and premium (usually 92 or 93). These levels vary from state to state. For example, one state may require all premium gasoline to have an octane of 92 or above while another state may allow 90 octane to be labeled premium.

When you read your owner's manual, be sure to note the precise octane level your car requires. Then look for that level rather than relying on a generic term like "regular" or "premium."