Saving Fuel AND Your Pocketbook – Do’s and Don’ts Part I (Don’ts)

CNN Money recently ran a good article on 6 gas-savings myths which is a good read for any of you who really do want to conserve fuel and the pocket-book it is taking a bigger chunk out of everyday. So, before I get to nine gas-saving tips, here are the six (plus one!) myths:


  • Fill your tank in the morning
    Sure, cold fuel is denser than warm fuel, but we’re talking gas, not water, and unless you’re living in Northern Canada near the arctic, the difference in volume is non-existent. Furthermore, the temperature difference of gasoline coming out of the nozzle varies little over the course of the day, so, as Consumer Reports rightly points out, there is little benefit to pumping during the coldest part of the day.
  • Change your air filter
    Modern engines have computer sensors that automatically adjust the fuel-air mixture as the engine’s air supply is reduced over time by an air filter that slowly clogs. Thus, the fuel savings from replacing your air filter more than necessary will be nonexistent.
  • Use premium fuel
    Premium fuel may be “recommended”, but it is definitely not “required”. Modern engines automatically adjust spark plug timing depending on the grade of fuel detected. You’ll get a slight reduction in horse-power, but you won’t get any fuel savings.
  • Pump-up your tires
    Under-inflated tires will increase fuel consumption, but over-inflated tires will not significantly decrease fuel consumption, because the reduced friction will not be that significant at normal driving speeds. Furthermore, the decreased traction will significantly increase your risk of crashing at speeds where fuel savings (theoretically) starts to kick in.
  • Turn off the A/C
    At slower speeds, modern A/C will cost you about 1 mpg, so, in an average economy vehicle, you could theoretically increase fuel economy about 4% by turning off the A/C in the city. However, at higher speeds rolled-down windows greatly increase aerodynamic drag, which increase fuel consumption, and A/C actually saves you fuel. Thus, if you make efficient use of the A/C (i.e. don’t try to cool your car to 15 and use the recycler feature for a quicker initial cooling once the air in your vehicle reaches a temperature lower than outside), the net is that the fuel consumption by modern A/C technology, on average, is negligible.
  • Use Bolt-ons and Pour-Ins
    Before you buy any device or additive to make your car more fuel-efficient, ask yourself the following “if there was such a device, wouldn’t the car manufacturer or fuel provider be selling this device, especially given the premium they could charge for their car or fuel with today’s fuel prices“? Most are just sugar pills, sold by con-artists who know that many of us will be just as happy with a placebo as a real pill (if we don’t know we’re getting the placebo).

Unfortunately, the article missed my favorite MYTH:

  • Go standard.
    Unless you drive like a pro, you’re not going to save any gas going standard and, in fact, you might actually consume more gas AND wear your engine out faster. Most modern automatic transmissions are so good at detecting when to switch gears that the maximum fuel savings from going standard is about 1 mpg. But chances are, unless you’re a very good driver, you’re not going to see any savings on average.

In our next post, we’ll discuss what you can do.