For the first time in over 15 years, increased engine and transmission problems in 2011 model year cars have contributed to a decline in vehicle dependability in J.D. Power's annual Vehicle Dependability Study.

Ordinarily you might put this down to the luck of the draw--an occasional drop is almost inevitable.

But there's a worrying correlation between these results and the trend for smaller, more fuel-efficient engines of the last few years.

According to J.D. Power's results, there have been ten more reported problems per 100 vehicles for smaller four-cylinder engines than in the previous year's survey--notably more than for older five and six-cylinder engines.

J.D. Power notes that fuel economy is a primary purchase motivator for many customers, but in striving for greater efficiency, "automakers must be careful not to compromise quality".

There's been a notable increase in problems such as engine hesitation, rough transmission shifts and lack of power with the new units, leading to the new engines' poor showing in the 2013 survey.

MORE: Do Small Turbo Engines Really Give Better Gas Mileage?

Low dependability has the potential to do more harm than fuel efficient engines do good, too.

J.D. Power says that poor dependability "creates avoidance", with customers more likely to change to a different vehicle next time around if they experience problems with their current car.

If such problems are directly related to newer, high-tech, downsized efficient engines, there's every chance that a customer may be inclined to pick a vehicle with lower efficiency but higher dependability next time around.

Not that it's all bad news for brands touting efficient vehicles: segment winners in this year's study include the Honda Fit, Chevrolet Volt, and the Lexus ES, GS and RX. The Volt in particular, a vehicle that many consider quite complex, shows that efficiency doesn't automatically mean low dependability.

General Motors ranked highly in this year's survey, all its brands finishing above the industry average for low reported problems. Lexus tops the list, by some margin over Mercedes-Benz and Cadillac.

Would low dependability for the latest breed of fuel-efficient four cylinder engines put you off them for your next purchase? Leave your thoughts in the comments section below.


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