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Making decisions at the pump

Everything about cars has changed over the years, including the gasoline most of them run on. There are several types of gas for cars, so it's important to have the right information for your vehicle and budget.

Types of gasoline

Chances are that your vehicle is just fine with the cheapest option at the gas pump. However, it’s worth checking to be sure. With modern engines having higher compression ratios and turbochargers, the recommendation for premium fuel is more common than it once was. Check your owner’s manual to confirm what type of gas should be used in your specific vehicle.

The octane rating

In Oregon and most other places that aren’t at high elevations, you’ll recognize the octane rating as those various numbers at the pump. A minimum octane rating of 87 is the most affordable, with 91 representing the midgrade and premium fuel at a minimum of 93. So what’s the real difference between them? If you drive one of the millions of vehicles recommended to run on regular fuel, the only difference for you is the price. There is no measurable benefit to “treating” your car to a tank of premium fuel. However, if you drive a car that requires premium, that's what should be used. The higher compression ratio of these engines could knock and run into other trouble with gas that has a lower octane rating.

Gas quality

It’s true that most gasoline in a given region likely came from the same refinery. However, that’s before a vast network of vendors and suppliers get ahold of the gas, which is eventually stored in a wide range of conditions. Gas stations and other storage facilities that have not been adequately maintained put the gasoline at risk of water contamination and other potential problems.


There are a variety of fuel additives you can buy anywhere from an auto parts store to the big box store just down the road. But did you know that much of the gas you get from reputable gas stations already has additives for keeping your engine and its exhaust clean? This is often referred to as Top Tier Gas, and that’s what you should use in your vehicle. It’s the type of gas you can expect to get at most name brand gas stations. Some places might try to up-sell additives in their gas, but newer and low-mileage engines probably don’t need the additional additives.

Symptoms of bad gasoline

It’s rare to get bad gas today, but it does still happen. Bad gas is most likely gas that has been contaminated with water. Depending on the level of contamination, you may notice a drop in fuel economy or something more serious like an engine that won’t start or run reliably. There are fuel additives with isopropyl alcohol that can help the engine deal with the water in the fuel. If that doesn’t solve the issue, your best bet is to let the pros take care of it. There’s a chance that the entire fuel system will need to be completely cleaned out.


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Meet Laura Augustine

Laura Augustine has worked as a finance assistant at Capitol Auto Group for 7 years. She is the proud mom of three kids (four, if you count her husband Chad): Ariel, age 23; Claudia, age 22; and Bryson, age 18. As a family, they love to go fishing and boating at Detroit Lake, and they also have four Saint Bernard Dogs: Grace, Ted, Jerry and Stuart.


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