In an article published on May 15, CNNMoney.com reports on six methods for saving fuel that do not work, but that persist as myths, especially as gasoline prices head steadily for the $4 per gallon mark.
The article debunks the idea that filling your tank early in the morning actually garners more bang for the bunk as fluids have greater density at lower temperatures. Unfortunately, data gathered by Consumer Reports indicated the temperature of the liquid at the nozzle does not vary significantly by time of day.
By the same token, premium fuel, which as already reached the $4 mark, is not required, only recommended, for some models and does not significantly enhance performance. Regular, and less expensive, gasoline will not hurt the engine and only slightly reduces the output of horsepower.
Some people believe that sweating through the summer with the air conditioning off is a fuel saving measure. In reality, it's an unnecessary discomfort. Running the air conditioner will only reduce fuel economy about a mile per gallon. Not enough gain to justify the pain for the driver on hot humid days.
Most importantly, the article cautions against falling for gas-saving additives that, when poured in the tank, purport to dramatically increase miles per gallon received. At best the additives do nothing, at worst they will damage the engine.
Without question, desperate people are ready to take desperate measures, but when it comes to fuel economy, evidence suggest there are more myths than facts. The best strategy is to keep a well-mained engine, drive at a reasonable rate of speed, and minimize braking as much as possible.