“It’s a measurable change, but not a dramatic increase,” David Sargent, vice president of global automotive at J.D. Power, said in a telephone interview. “It’s a blip, we think, and it’s driven largely by two things.”

First, vehicles that are all-new or that have undergone major redesigns continue to have more problems than those that carry over without significant changes. On average, all-new vehicles or major redesigns had 128 problems per 100 vehicles; vehicles without significant changes had 113. And, among the all-new vehicles, the increase in problems was mainly, once again, in the areas of voice recognition, Bluetooth pairing and audio systems. Consumers continue to report that this new technology is hard to understand, difficult to use, or simply does not always work as designed, according to the study.

The second issue was the brutal winter, Mr. Sargent said. In warm-weather states, those surveyed reported the same number of problems as in 2013, which was 114 problems per 100 vehicles. In cold-weather regions, they reported 117 problems per 100 vehicles, compared with 112 in 2013.

Of the 32 brands included in this year’s study, 13 improved, one stayed the same and 18 did worse. Following Porsche, which had a score of 74 problems per 100 vehicles, in the top 10 were Jaguar (87), Lexus (92), Hyundai (94), Toyota (105), Chevrolet and Kia (tied at 106), BMW and Honda (tied at 108) and Lincoln (109).

The study found that Fiat had the most issues, with 206 problems per 100 vehicles. Rounding out the bottom five were Jeep (146), Mitsubishi (145), Scion (140) and Mazda (139).