Time for a few words of wisdom about octane, sales of the higher octane, thus more expensive, fuels have fallen off with the high gas prices. First read your owner’s manual, you know that manual under all the junk in the glove box, if you don’t have one look online. Heed the advice they give on minimum octane for your vehicle. If you use to low of an octane you won’t hear a ping as in the old days, as the knock will retard the timing. But what will happen is the engine will carbon up, no matter how many road miles you put on, and this can cause major problems with no warning till it is too late. Knock sensors detect detonation and automatically retard the spark to compensate. The delay means maximum gas expansion occurs when the piston is farther along in its down stroke and thus there’s more room in the cylinder head. This reduces peak cylinder pressure, eliminating knock but also giving you less power, poorer mileage and carbon build up.Regular gas has an octane rating of 87, midgrade 89, and premium 91 or 92. (Octane ratings are lower in the West Mountains. All grades of Fuel contain roughly the same amount of heat energy, or power.. Rather, a higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car’s cylinders ignites spontaneously due to compression or excess carbon Independent of the combustion by the spark plug. Instead of a controlled burn, you get an explosion. To avoid this, high-octane gas is formulated to burn slower than regular, yes slower. So it will ignite without benefit of spark.Using high octane when you car does not require it is a waste of money, it will not increase your power or mileage. The one major difference is the additives put into the fuel. One example was Amoco silver, which has changed since going BP; it contained several excellent additives such as a cleaner that produced excellent results. I know of no Major that has a fuel like this Mobil is the closest but still not worth the money if your vehicle does not call for higher octane.If you insist on spending some extra dollars add a can of sea foam to your tank on every 3rd or 4th fill and you will perhaps see some results, but it is more of a maintance item that gallonage increase.