Toyota will replace the accelerator pedals on millions of cars, including this 2010 Camry, and install brake override systems on many of them to prevent runaway acceleration.

Just weeks after it began advising 3.8 million owners that their cars would be called back due to floor mats that can jam the accelerator, Toyota now says it will also replace gas pedals in vehicles that could experience sudden, uncontrolled acceleration.

The automaker initially said that loose or poorly installed floor mats could become jammed under the accelerator making it difficult to slow the vehicle.  The maker now plans to shorten existing pedals and will install entirely new pedals when they become available next April.

“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 company said.

Today’s announcement adds a new element to one of the largest safety recalls in U.S. automotive history and follows just a day after the increasingly troubled Japanese maker said it would have to make potentially extensive repairs to 110,000 of its full-size Tundra pickups, which are prone to excessive corrosion.  The National Highway Traffic Safety Administration found that this could lead to brake system failure and to spare tires falling off the trucks.

The bigger recall was prompted by a series of accidents, including one in August in which a California Highway Patrol officer and three members of his family were killed when his Lexus ES350 suddenly surged out of control reaching speeds of 120 mph before striking an SUV, launching off an embankment, rolling several times and bursting into flames.

There’s been an ongoing debate over the underlying problem, though Toyota continues to insist it is the result of mats that can catch under the pedals.  The NHTSA is also looking at the basic design of the floor pans of the affected vehicle, but has so far ruled out unexplained electrical or mechanical glitches.

Nonetheless, Toyota is facing a number of lawsuits, including at least one class action, claiming such gremlins are at play.  Similar claims were raised, 20 years ago, when the Audi 5000 sedan was the target of claims concerning so-called “Unintended Acceleration.”  Eventually, however, the government ruled that the problem was the result of driver error.  Still, Audi changed the layout of its own pedals, on future models, to reduce such a likelihood.

Impacted by the recall are the following vehicles:

• 2007 to 2010 model year Camry
• 2005 to 2010 Avalon
• 2004 to 2009 Prius
• 2005 to 2010 Tacoma
• 2007 to 2010 Tundra
• 2007 to 2010 Lexus ES350
• 2006 to 2010 Lexus IS250
• 2006 to 2010 Lexus IS 350.

Toyota said, during a media conference call, this morning, that it will ask owners to come into a Toyota dealership, starting in January, to have the gas pedals shortened, which should reduce the likelihood of catching on a loose floor mat.  Until then, the company has asked motorists to remove any mats on the driver’s side.  Replacement pedals will become available next April, the company said.

Spokesman Irv Miller added that Toyota is, “very, very confident that we have addressed this issue,” and again ruled out the possibility of an electronic or electro-mechanical glitch.

Some vehicles, including Camry, Avalon and Lexus ES350, IS350 and IS250, will also have brake overrides installed as an additional precaution.  That added step provides “an extra measure of confidence,” the NHTSA said, in a statement.

Toyota has also advised owners of vehicles with keyless start that, if necessary, they can shut the engine down by holding the start button for three seconds.  With a standard ignition, the motorist should turn the key to the ACC position to avoid locking the steering column.  Once the engine stops, the vehicle will lose power assistance to both brakes and steering.

So far, the federal government says it has linked 5 deaths and two injuries to accidents related to floor mats in Toyota vehicles, though some independent experts claim the numbers are now in the range of 16 deaths, several hundred injuries and at least 2,000 incidents where vehicles surged – at least briefly – out of control.

The problems experienced by Toyota in the U.S. could lead to recalls in other parts of the world, including the Japanese home market, a spokesman for Toyota Motor Company said.

The huge recall, and yesterday’s smaller safety action on 2000 to 2003 model-year Tundras, only worsen what is a growing list of problems for the world’s largest automaker.  Sales have slid sharply this year at a company that normally seemed oblivious of economic downturns.  There have been some quality problems, in recent years, though most have been corrected, according to various industry analysts.  Nonetheless, Toyota was notably snubbed in the latest Total Value Awards, from Strategic Visions, which measures not just quality but value and consumer perceptions of the fun-to-drive factor of their vehicles.

Prior to today’s announcement, Toyota officials had said they expect to post a global loss of more than $2 billion for the fiscal year ending next March.  Capping all its problems, Toyota slipped to number two, in the global sales sweepstakes, behind German rival Volkswagen, for the first nine months of 2009.