Close to six million vehicles can run on E85 as well as regular gas.

NPR: Ethanol-Based Fuel Enthusiasts Face Lack of Pumps

Still, that's hardly a noticeable fraction of the 170, 000 regular gas stations in this country that still don't sell E85 fuel.

NPR: Ethanol-Based Fuel Enthusiasts Face Lack of Pumps

If drivers of premium-required cars try to burn regular gas, they could damage their engine due to high exhaust-gas temperatures and knocking.

FORBES: Do You Really Need Premium Gas?

It burns cleaner than regular gas, reducing pollution from exhaust.

NPR: Ethanol-Based Fuel Enthusiasts Face Lack of Pumps

Lowry says that biodiesel is currently cheaper than regular gas.

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According to Ford and Toyota, the jointly-developed new hybrid powertrain will offer better fuel efficiency while offering the same capabilities like towing capacity expected of a regular gas-powered truck.

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And it takes regular gas.

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The allowed deduction is for the business-use percentage of the lease price plus regular expenses (gas and so on) minus a small adjustment (the lease inclusion amount) that is smaller this year than in the past.

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My budget became so tight that I felt each expense keenly: The regular bills, the rising costs of food, gas, and doctor co-pays.

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Similarly, Gas Buddy and Local Gas Prices can come in handy to help locate the cheapest gas prices in a given area for regular, midgrade, premium and diesel grades.

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Those cars for which the manufacturer has recommended premium gas, according to Edmunds, can function fine on regular.

FORBES: Do You Really Need Premium Gas?