Ford Motor Co. supplanted Toyota as leader of the pack in J.D. Power and Associates' annual initial quality rankings released Wednesday, grabbing more individual awards than any other automaker for the first time since 1998, when it tied for the top spot.

Ford ranked highest in five of 19 segments in this year's survey. That's two better than in 1998 — the last time a U.S. automaker was on top — when Ford tied with Toyota and Honda.

The Dearborn automaker earned segment awards for the Ford Mustang, Lincoln Mark LT, Lincoln MKZ, Mercury Milan and Mazda MX-5 Miata. Mazda is 33.4 percent owned by Ford.

Porsche again dominated the overall ranking of brands, averaging 91 problems per 100 vehicles, as it had last year. That compared with a 2007 industry average of 125 problems per 100 vehicles. Last year it was 124.

Toyota Motor Corp., which grabbed the top spot in 11 segments last year, captured only four this year — the 4Runner, Sequoia, Tacoma and Lexus RX350/RX400h.

Ford's Lincoln brand, which jumped from 12th to third in overall vehicle quality, averaged 100 problems per 100 vehicles. It was behind Porsche and Toyota's Lexus luxury brand, which averaged 94 problems per 100 vehicles.

"We saw dramatic improvement from Lincoln," said Neal Oddes, J.D. Power's director of product research and analysis. "It was a fantastic year for the Mercury Milan, with dramatic improvements in terms of defects."

Overall, he said, Ford's strength came from new launches such as the Edge, MKX and MKZ.

Ford spokeswoman Anne Marie Gattari said those launches "speak volumes about what we're doing right."

"What we saw today is the result of several years of adhering to our design and manufacturing processes with complete discipline," she said. "It took some time for the results to be evident."

Toyota had seen its list of quality leaders decrease in a quality study released Monday by Strategic Vision Inc., a San Diego-based market research company and consultant to automakers. Despite improving its overall quality, Toyota led in one category in that study — down from four in 2006. South Korean automaker Hyundai Motor Co. led in five categories, outperforming its Japanese, European and U.S. competitors. Last year, it had no winners.

Joe Ivers, J.D. Power's executive director of quality and customer satisfaction, said there's no clear answer for Toyota's drop. But several vehicles brought its quality performance down this year, including the Corolla, Prius and Lexus models.

It is worth noting, he said, that Toyota executives have been speaking publicly about their concerns about maintaining its historically high quality during a time of rapid growth.

"We're not used to seeing their vehicles go backward from a quality standpoint, and several of them did," he said. "It's no big change, but when things go backward for Toyota, it's unusual."

Toyota spokesman Mike Michels said the company was pleased with its results, adding that Toyota was the second-ranked non-luxury brand and stayed in the top 10 overall. Lexus also maintained its second-place ranking overall.

Michels said the LS460, which for the first time was not the top-ranked in its segment, came in a close second to the Audi A8 and Mercedes Benz S-Class, which tied for first. Still, the company also was pleased with that showing, since it was a redesigned model and had just been shipped to dealers before the survey-taking began.

Michels said small shifts such as these make a huge difference as the quality gap has narrowed among automakers.

"In our view, if you really look at this, we're starting to see differences that are not statistically significant," he said.

"The (Initial Quality Survey) is not the whole picture when it comes to customers' perceptions and the information they have on quality. We think that long-term quality and durability are what people base their buying decisions on."

In the J.D. Power survey, Hyundai fell from third overall to 12th. Oddes said relaunched vehicles such as the Santa Fe did not do as well as the automaker had hoped. On the plus side, the redesigned Elantra performed well in its segment.

Lincoln was followed by Honda, Mercedes-Benz, Jaguar and Toyota. Honda, with the fewest problems per 100 vehicles among non-luxury brands, improved in the ranking to fourth from sixth in 2006.

The most improved nameplates in the study are Land Rover, Saab and Mercedes-Benz.

Ivers said Mercedes-Benz's improvements have been significant and speedy across its product line. It grabbed the top spot in three segments, and notable was its S-Class going from "worst to first" as it launched a redesigned model.

"A lot of people avoid buying a vehicle in its first year of production, but Mercedes, with its S-Class, got everything right," he said.

J.D. Power also gave the Platinum Plant Quality Award for producing vehicles yielding the fewest defects to Ford's Wixom Assembly Plant, which stopped making cars May 31. The Detroit-area plant produced the Lincoln Town Car, which averages 35 problems per 100 vehicles.

It was the first North American assembly plant to receive the honor since 1999.

For the study, Westlake Village, Calif.-based J.D. Power collected responses from more than 97,000 buyers and lessees of new 2007 model year vehicles after 90 days of ownership.

This year's survey included 228 questions and asked for information specifically about design and production, such as defects and malfunctions.