He also said that even though the differences seem insignificant, they have an effect on consumers and whether they will stay with a brand or recommend it to others.

"For every small, incremental increase in quality, you will get more customers coming back to your brand," Sargent said.

Sargent said rising gas prices had some effect on the rankings this year. While the average number of problems with vehicles' fuel consumption stayed the same as in 2007, the owners of large vehicles were more likely to complain about high fuel consumption, while the owners of small vehicles were less likely to complain.

"I believe this is entirely due to increased gas prices and people's sensitivity to the issue," Sargent said.

Sargent also said hybrid vehicle owners were also slightly more likely to complain about fuel consumption.

J.D. Power also gave awards to the plants which produce the vehicles with the fewest mechanical complaints and defects. The Mercedes-Benz plant in Sindelfingen, Germany, was the best overall, averaging 33 problems per 100 vehicles. In North and South America, the winner was the Toyota plant in Baja California, Mexico, which produces the Toyota Tacoma. In Asia, the top plant was Toyota's Fujimatsu plant in Japan, which makes the Toyota Prius.