WASHINGTON – Toyota Motor Corp said Wednesday it will replace accelerator pedals on about 4 million recalled vehicles in the United States because the pedals can get stuck in the floor mats, another blow to the reputation of the world’s largest automaker.

Toyota said dealers will offer to shorten the length of the gas pedals by about 3/4 inch beginning in January, as a stopgap measure while the company develops replacement pedals for their vehicles. New pedals will be installed by dealers on a rolling basis beginning in April, and some vehicles will have brake override systems installed as a precaution.

Toyota announced the massive recall in late September and told owners to remove the driver’s side floor mats to keep the gas pedal from becoming jammed.

Popular vehicles such as the Toyota Camry, the top-selling passenger car in America, and the Toyota Prius, the best-selling gas-electric hybrid, are among those getting fixed. The recall also included the luxury Lexus ES350, the vehicle in a fiery fatal accident in California that focused public attention on the danger.

“The safety of our owners and the public is our utmost concern and Toyota has and will continue to thoroughly investigate and take appropriate measures to address any defect trends that are identified,” the Japanese automaker said in a statement.

Toyota spokesman Irv Miller said the company was “very, very confident that we have addressed this issue” with the new fix. Toyota has found “no reason to believe that there is a problem with the electronic control systems,” he said.

Toyota officials said the floor mats are only sold in the U.S. and the recall would be limited to North America.

Toyota declined to provide a cost estimate for the fix, but analysts said it would be extremely expensive because of the extensive repairs involved and the manufacturing of new pedals. Toyota also said it would provide newly designed replacement floor mats for the driver and front-passenger side.

The recall represents the latest blemish for Toyota, which developed a sterling reputation for quality in the US by selling reliable family vehicles but faced challenges as it rapidly expanded. While recalls do not always indicate diminished reliability, Toyota executives have expressed concern about large numbers of recalls and pushed for improved quality controls.

In a separate action, Toyota announced Tuesday that it would recall 110,000 Tundra trucks from the 2000-03 model years to address excessive rust on the vehicle’s frame.

“Their reputation has taken a hit because the actual quality has taken a hit,” said Aaron Bragman, an automotive analyst for the consulting firm IHS Global Insight. “That’s absolutely critical for Toyota to get that fixed because that’s the central pillar that they’ve built their business on.”

The accelerator pedal recall is Toyota’s largest in the US and the seventh-largest ever in the U.S., according to the National Highway Traffic Safety Administration. It includes 3.8 million vehicles, including the 2007-10 model year Camry, 2005-10 Toyota Avalon, 2004-09 Prius, 2005-10 Toyota Tacoma, 2007-10 Toyota Tundra, 2007-10 Lexus ES350 and 2006-10 Lexus IS 250/350. Toyota officials said about 4 million vehicles would be covered, including new cars and trucks sold since September and others manufactured since the recall was announced.

It was prompted by a high-speed crash in August involving a 2009 Lexus ES350 that killed a California Highway Patrol officer and three members of his family near San Diego. The Lexus hit speeds exceeding 120 mph, struck a sport utility vehicle, launched off an embankment, rolled several times and burst into flames. In a frantic 911 call, a family member told emergency responders that the accelerator was stuck and the driver couldn’t stop.

NHTSA investigators determined that a rubber all-weather floor mat found in the wreckage was slightly longer than the mat that belonged in the vehicle, and could have snared or covered the accelerator pedal

The government has attributed at least five deaths and two injuries to floor mat-related unintended acceleration in the Toyota vehicles and has received reports of more than 100 incidents in which the accelerator may have become stuck. A Massachusetts-based safety consultant who has investigated the Toyota cases, however, has found more than 2,000 incidents involving 16 deaths and 243 injuries potentially tied to the Toyota gas pedals.

To fix the problem, Toyota and the government said dealers will shorten the length of the accelerator pedal on the recalled vehicles and in some cases remove foam from beneath the carpeting near the pedal to increase the space between the pedal and the floor. They said owners of the ES350, Camry and Avalon would be the first to receive notification because the vehicles are believed to have the highest risk for pedal entrapment.

Toyota also plans to install a brake override system on the Camry, Avalon and Lexus ES350, IS350 and IS250 models, Toyota and NHTSA said. The brake override system will ensure the vehicle will stop if the brake and the accelerator pedals are applied at the same time.

Toyota plans to make the brake override system standard equipment throughout the Toyota and Lexus lineup by the end of 2010.

The automaker and government regulators have been discussing a potential fix for several weeks. Toyota urged owners in September to remove driver’s side floor mats and not replace them until the company had determined a fix. The automaker said unhooked floor mats or replacement mats stacked on top of the originals could lead to stuck accelerators.

In November, Toyota issued a statement saying NHTSA had confirmed “that no defect exists in vehicles in which the driver’s floor mat is compatible with the vehicle and properly secured.” But in a rare rebuke, NHTSA accused Toyota of releasing misleading information about the recall, saying removing the mats did not “correct the underlying defect.” Toyota said it was not the company’s intention to mislead anyone.