Filed under: Acura , Buick , Cadillac , Chevrolet , Honda , Lexus , Mercedes-Benz , Scion , Toyota For the first time since 1998, J.D. Power and Associates says its data shows that the average number of problems per 100 cars has increased . The finding is the result of the firm’s much-touted annual Vehicle Dependability Study, which charts incidents of problems in new vehicle purchases over three years from 41,000 respondents. Looking at first-owner cars from the 2011 model year, the study found an average of 133 problems per 100 cars (PP100, for short), up 6 percent from 126 PP100 in last year’s study, which covered 2010 model-year vehicles. Disturbingly, the bulk of the increase is being attributed to engine and transmission problems, with a 6 PP100 boost. Interestingly, JDP notes that “the decline in quality is particularly acute for vehicles with four-cylinder engines, where problem levels increase by nearly 10 PP100.” Its findings also noticed that large diesel engines also tended to be more problematic than most five- and six-cylinder engines. Among individual brands, Lexus has taken the prize for most-dependable nameplate for the third year in a row, registering just 68 problems per 100 vehicles. Mercedes-Benz , Cadillac , Acura and Buick rounded out the top of the class with 104, 107, 109 and 112 PP100, respectively. Broken down into specific models, General Motors brands continued their success, winning eight dependability awards for its 2011 models, including prizes for the Chevrolet Volt , Cadillac Escalade and Buick Lucerne . Toyota followed that up with seven prizes split between its Lexus, Toyota and Scion nameplates, while Honda tallied six wins.