Gas saving facts and fallacies exposed

You've probably heard the same advice we have about the best practices to keep your car running well.

We've learned that some of that advice is true, and some is just plain fiction.

You might have heard it's a good idea to pass up a gas station if you see a tanker truck unloading fuel. Here's what 35-year mechanic Mark Kuhlmeier with Kuhly's Import Specialists in Quincy says about that:

Kuhly said, "Come back in the next 3-4 hours. That will allow some of the dirt sediment that has been agitated to settle."

We also asked if it's better to let your car's engine warm up before driving this time of year. Kuhlmeier says that isn't so. In fact, that's a good way to eat fuel fast. Modern engines work more efficiently when driving than when idling.

Kuhly said, "The car is designed to be started once the windows are clean enough to see, drive that vehicle because a moving vehicle will warm up faster than one that is sitting still. Believe it or not, experts with fuel injection say it's not as important as it used to be. Now with the advent of fuel injection and the good driveability that the automobile provides you, you will find the heater works better and defroster will, too."

But in the summer time, it may be more cost efficient to let your car long as you don't run the gas guzzling air conditioner.

Kuhy said, "It's the air conditioner that is bad in the summer time. It's a proven fact that you can let an automobile idle up to four hours and it will use less than four ounces of fuel. It's better off to let your car idle than turning it on and off. Why is that? Because it takes more fuel to start the vehicle than it takes to maintain it, but wintertime is a different deal -- in winter it eats a lot of fuel."

As you can guess, Kuhlmeier says your air conditioner is one of the biggest gas-mileage thieves. It robs almost 15 to 20 percent of your fuel economy, or 8 miles to the gallon. So use it at your own risk to your wallet.

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