A School of Mines professor has tracked his gas purchases since 1989 and prefers 87 octane.

87 octane gasoline, often called "regular" gas, is one of the most commonly used fuels in the United States. But what gives it that 87 rating is a word you've probably heard a time or two: Ethanol.

Labeling different gases as “regular” and “premium” is a bit misleading, as many cars only require regular gas and should only run on regular gas. Premium gasoline is not necessarily a luxury product ...

Add Yahoo as a preferred source to see more of our stories on Google. With the price of regular unleaded gasoline still in the $4-a-gallon range, the comparative price of premium is kind of a bargain ...

If you've ever fueled up in Colorado, you might have noticed something unusual about the gas octane ratings at the pump – specifically, the availability of 85-octane gasoline. This lower octane fuel ...

Dear John: I never noticed this before because I always used 87 octane gasoline. My new car requires 89 octane. The price difference between 87 and 89 ranges between 20 and 60 cents, depending on the ...

With the price of regular unleaded gasoline still in the $4-a-gallon range, the comparative price of premium is kind of a bargain at many stations. Really. When the price of regular surged this spring ...