Fuel Economy Gauges Don't Always Tell the Truth, Reports Edmunds.com
SANTA MONICA, Calif. — May 16, 2011 — Fuel economy gauges, which now come standard in 92 percent of new cars, may be over-representing your car's fuel efficiency, according to tests conducted by editors at Edmunds.com, the premier online resource for automotive information.
A total of 14 tests in seven vehicles found that the MPG gauges were 5.5 percent inaccurate, on average. In the case of the 2010 Ford Escape Hybrid, the MPG claims were overstated by as much as 19 percent and for the 2010 Volkswagen Jetta SportWagen TDI, the gauge was off by 16 percent.
"A 5.5 percent error in a car's estimated fuel usage might not seem like a big deal over a single tank of gas, but it adds up over the typical five-year period of car ownership," said Phil Reed, senior consumer advice editor at Edmunds.com. "If a driver uses the fuel economy meter as the basis for budgeting a 25 mpg car, he would plan for five-year fuel costs of $12,000, assuming fuel stays at $4 per gallon. In reality, the figure would be $12,660. The discrepancy is even larger for vehicles that have worse average fuel economy."
Many car companies contacted by Edmunds.com did not respond to questions about Edmunds' findings. A GM spokesman, however, suggested that varying levels of ethanol mixed in gasoline may have an adverse impact on a car's fuel economy, since the substance provides less energy. A Honda spokesman said that drivers should use fuel economy gauges as "a driving-efficiency tool, not a precise measurement of fuel economy."
To get a true estimate of your car's fuel economy, Edmunds.com suggests taking the matter — quite literally — in your own hands. There are several iPhone apps that can help you log and monitor your car's fuel economy. Edmunds.com reviewed four of these apps last month at http://www.edmunds.com/car-technology/road-test-of-4-fuel-efficiency-iphone-apps.html. For the technologically challenged, drivers can also simply keep a handwritten log and maintain the data themselves.
For more details on Edmunds.com's MPG gauge findings, please visit "Your Fuel Gauge is Fibbing" at http://www.edmunds.com/fuel-economy/your-fuel-economy-gauge-is-fibbing.html.
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Edmunds.com Inc. publishes Web sites that empower, engage and educate automotive consumers, enthusiasts and insiders. Edmunds.com, the premier online resource for automotive information, launched in 1995 as the first automotive information Web site and hosts the most established automotive community online. Its mobile site, accessible from any smartphone at www.edmunds.com, makes car pricing and other research tools available for car shoppers at dealerships and otherwise on the go. InsideLine.com is the most-read automotive enthusiast Web site. Its mobile site, accessible from any smartphone at www.insideline.com, features the wireless Web's highest quality car photos and videos. AutoObserver.com provides insightful automotive industry commentary and analysis. Edmunds.com Inc. is headquartered in Santa Monica, California, and maintains a satellite office in suburban Detroit. Follow Edmunds.com on Twitter@edmunds and fan Edmunds.com on Facebook at http://www.facebook.com/edmunds.