Do you NEED higher octane fuel?

A "knock" or "ping" occurs when part of the fuel-air mixture in one or more of your car's cylinders ignite spontaneously due to compression, independent of the combustion initiated by the spark plug.

If your car runs poorly or "pings" on the grade of gas recommended, it may need servicing, rather than using a higher grade of gas.

If switching to high octane improves mileage, it may mean that your engine, or its control system needs repair.

The higher the octane, the higher the price.

This gas card offer looks pretty good!

Octane has nothing to do with the gasoline's performance, just its volatility factor in the combustion chamber.

The higher the octane, the more stable the gas in the combustion chamber environment.

High performance cars need higher-octane gasoline, because the combustion chamber environment is much hotter. Experts from the Automobile Association of America (AAA) say about five percent of cars sold in the US actually require premium gasoline.

Yet, premium gasoline accounts for 20 percent of all gasoline sold in the US. If your car does not require higher octane gas, then you shouldn't buy it.

For example, if your car takes 87 octane and the pumps have 85 octane and 89 octane, when filling your car, fill half the tank with 85 octane and the other half with 89 octane and this will give you an equivalent of 87 octane.

Actually, octane has nothing to do with the gasoline's performance, just its volatility factor in the combustion chamber. The higher the octane, the more stable the gas in the combustion chamber environment.

Drivers should use the octane level your vehicle's manufacture recommends. Buying higher-octane fuel is a waste of money. Higher-octane fuel pollutes more, and it costs more. It's always smarter to follow the manufacturer's recommendation on the level of octane to use.

People believe buying the "premium" will make their cars run better, but it makes your engine run hotter and can cause more harm than good.

In most of the U.S., regular gas has an octane rating of 87, mid grade is 89, and premium is 91 or 92. Using high-octane fuel reduces pre-ignition in the upper regions of the combustion chamber, which can damage valves, and pistons if allowed to go for long periods of time. Resist buying higher-octane gas for premium performance. It can cause other problems to your engine.