Land Rover, Dodge, Mitsubishi, Jeep and Volkswagen finished at the bottom of the latest report.
Across the industry, owners of three-year-old 2010 cars and light trucks reported 126 problems per 100 vehicles, an all-time low and a 5 percent improvement from 132 problems per 100 on 2009 models a year ago.
"Manufacturers keep improving product quality," said David Sargent, Power's vice president of global automotive.
Domestic nameplates improved at a slightly higher rate than imports, and narrowed the dependability gap to 10 problems per 100 vehicles surveyed, Power said.
And for the first time since Power started tracking it in the 2009 study, all-new and redesigned vehicles had higher quality than carryover vehicles, Sargent said.
Launch vehicles, models that were significantly redesigned or new for 2010, averaged 116 problems per 100, while those carried over unchanged from the previous year scored 133.
"The rapid improvement in fundamental vehicle dependability each year is more than offsetting any initial glitches that all-new or redesigned models may have," Sargent said. "That juggernaut of improvement overcomes [traditional] launch problems.
"More importantly, it means that vehicles being launched today are very likely to be more dependable than three-year-old models are now."
Buick, Honda, Acura, Ram, Suzuki, Mazda and Chevrolet also finished above the industry average – 126 problems per 100 models studied.
Power tallies problems reported in the past 12 months by the original owners of three-year-old vehicles. The 2013 study released today covers 2010 cars and light trucks representing 32 brands. To create whole-number separation among brands, Power reports problems per 100 vehicles, with lower scores indicating greater reliability.
Dependability scores have improved steadily across the industry in the 24 years that Power has conducted the study. The average problems per 100 vehicles was 216 in the 2007 study, showing an improvement of almost a full problem per vehicle in six years.
Ram improves most
Consumers are less tolerant about problems with their cars and light trucks. Dissatisfied owners are less loyal to that brand based on earlier Power studies, which cross-match survey responses with data on vehicle purchases and trade-ins.
Of owners who reported no vehicle problems, 54 percent bought or leased a vehicle from the same brand the next time. For those with three or more problems, brand loyalty fell to 41 percent.
In the new study, 22 brands improved dependability from last year and nine slipped.
Ram posted the biggest one-year improvement, scoring 52 points better to finish with 122 problems per 100, jumping from No. 29 in 2012 to vault into the top 10 tied for ninth this year.
"Chrysler improved the Ram pickup remarkably between the 2009 and 2010 model years," Sargent said. That era also marked the U.S.-led rescue of Chrysler through an alliance with Italy's Fiat S.p.A.
Suzuki, which is exiting the U.S. auto market, Mazda, Chrysler, Infiniti and Kia also showed major gains in the study.
Power said Mitsubishi, Scion, Cadillac and Hyundai reported the biggest increase in problems in the study.
In this year's Power study, Lexus and Porsche had less than one problem per vehicle (under 100 per 100) and Land Rover had more than two (220 per 100).
Lexus rose to No. 1 last year from the fourth spot in 2011. The brand ranked as the industry's most dependable marque for 14 years until 2009, when Buick and Jaguar tied for No. 1. Porsche and Lincoln had taken top honors since then.
But most brands are grouped tightly in the middle, with less than a third of a problem, 29 per 100 per car separating No. 3 (Lincoln and Toyota tied at 112) from No. 22 (Hyundai at 141).
The industry's continuous improvement in long-term reliability is good news for U.S. car buyers, Sargent said.
"Consumers have more assurance than they've ever had," he said. "If you want to either keep your own car more than three years or are in the market for a late-model used car, you're in good shape."
Power said the most dependable 2010 model was the Lexus RX -- with 57 problems per 100 models surveyed. It's the first time an SUV or crossover has topped the list of models studied for long-term reliability.