In this time of high gasoline prices, the Teeming Millions need your guidance (well, at least I do). What is the difference between premium and regular gas, and is this difference worth the extra money? I normally put premium gas into my car because I don’t mind paying two or three extra dollars at the pump. Am I being scammed by the gas stations, or is the benefit to my car worth it? –Jeff, via e-mail

Best of Chicago voting is live now. Vote for your favorites »

Not to introduce a radical concept, Jeff, but have you tried reading your owner’s manual? If it says to use premium, my advice is to use premium. If it says regular, use regular. The fact that your note indicates no acquaintance with such matters suggests that you may in fact be a scam victim, assuming by this you mean “someone who believes what he hears in commercials.” I have a hard time working up much outrage over this deception, since discovering the facts requires so little effort. If you don’t mind paying the extra money for no reason, don’t expect the oil companies to suffer any pangs accepting it.

Using high-octane gas in a car designed for regular accomplishes little except more rapid combustion of your money. Some refuse to believe this, claiming, for example, that premium gives the family Toyota better mileage or more power. These people are on drugs. Others say premium is purer or contains detergents that will cleanse your engine of uncouth deposits. Likewise misguided thinking–government regulations require detergents in all grades of gasoline. (BP Amoco, I notice, asserts that its premium gasoline contains more detergents than legally required; if you think that’s worth 20 extra cents a gallon, be my guest.) Some automotive types claim that using premium in a car designed for regular will make the engine dirtier–something about deposits on the back side of the intake valves. I’ve also heard that slower-burning high-octane gas produces less power when used in ordinary cars. Believe what you like; the point is, don’t assume “premium” means “better.”