Whether gas prices are pushing $4 or dropping below $2, everyone wants to save a few bucks at the pump. And there are a lot of tips making the rounds to help you cut your fuel consumption. Unfortunately, many of them aren’t completely accurate.

Fuel Economy Myths

Here’s a list of five of the most common myths for getting better gas mileage:

  1. Fill Up in the Morning — The theory is that it’s cooler in the morning, so the gas will be denser; you’ll get more for your money. Improve Fuel Economy Myths - Cottman Man - Cottman Transmission and Total Auto Care

But gas is stored underground. The temperature swings during the day won’t affect the gas, so there’s no benefit to filling your tank in the morning over any other time of the day.

  1. Replace the Air Filter — This one’s a holdover from when fuel delivery was controlled through a carburetor. Back then a dirty air filter would cause the engine to run rich and waste gas.

But today’s cars use electronic fuel injection. If the air filter’s clogged, the system identifies the reduced air flow and reduces the fuel delivery to match it. The car may not have as much pep, but the gas mileage won’t be affected.

  1. Use the Cruise Control — This is the exact opposite of how to save gas. The idea is, if you apply the throttle slowly and smoothly, you won’t use as much gas. That part’s true.

But cruise control doesn’t work that way. When the cruise control system notices the car’s speed begin to drop, it opens the throttle… fast. And it works the throttle quickly to counteract changes in vehicle speed, with no consideration to gas mileage.

  1. Buy Over-the-Counter Gas Additives — You can’t walk past an automotive store without seeing additives that promise everything from better gas mileage to a brighter smile. And they’re all gluten free!

Fuel System Improvement

But will they improve your car’s gas mileage? Probably not; in fact they may actually damage your car’s fuel system.

Most of those additives use harsh solvents like acetone. They’ll loosen up deposits a little and may even improve the fuel delivery… at first. But they can damage the fuel pump and fuel injectors, and they burn off too easily, creating additional deposits in the combustion chamber.

There are professional services for cleaning the fuel system that work well for improving your car’s performance and gas mileage. But the over-the-counter additives? Usually not a good investment.