Toyota plans to recall as early as next week 3.8 million U.S. Toyota and Lexus models--its largest ever--to fix floor mats that may snag gas pedals and cause vehicles to accelerate at high speeds.

In the meantime, U.S. regulators are urging owners of the seven affected nameplates to remove their driver-side floor mats. The National Highway Traffic Safety Administration said it issued the warning because of continued reports of vehicles accelerating rapidly after drivers released the accelerator.

“This is an urgent matter,” U.S. Transportation Secretary Ray LaHood said in a statement. “We strongly urge owners of these vehicles to remove mats or other obstacles that could lead to unintended acceleration.”

The recall was sparked by an Aug. 28 accident in San Diego during which four people were killed in a Lexus, said Irv Miller, a spokesman for Toyota Motor Sales U.S.A. Inc.

The investigation is continuing, but he said a floor mat catching on the accelerator may have caused that crash.

“That prompted us to look more closely at reports from the field of similar incidents,” Miller said. He declined to provide a specific number of complaints that have been filed with NHTSA or say if the company has been sued.

“The San Diego accident was very tragic for all of us,” Miller said. “We want to make sure none of us has to relive that.”

Affected vehicles

The Toyota vehicles involved are 2007 to 2010 Camrys; 2005 to 2010 Avalons; 2004 to 2009 Priuses; 2005 to 2010 Tacomas and 2007 to 2010 Tundras. Lexus models are 2007 to 2010 ES 350s and 2006 to 2010 IS 250s and IS 350s.

In addition to unsecured floor mats, the company will be looking at the configuration of the pedals and the unique steps to shut off the engines with keyless ignition as possible causes for the unintended acceleration. Toyota said it has no evidence that faulty brakes or throttles have contributed to the problem.

Should a mat catch on the pedal, Toyota recommends that owners pull back the mat and dislodge it. If the mat doesn't dislodge, owners should:

-- Step firmly on the brake pedal with both feet;

-- Or shift into neutral and use the brake to stop the vehicle;

-- Or turn off the engine.

In September 2007, Toyota recalled an all-weather floor mat from some 2007 and 2008 Lexus ES 350 and Toyota Camry vehicles because of similar problems, NHTSA said.

Biggest previous recall

The automaker's largest recall to date was in October 2005 when it recalled about 900,000 vehicles for faulty steering relay rods.

The 3.8 million vehicles being recalled compares to Toyota's 2008 U.S. sales of 2.2 million Toyota, Lexus and Scion brand vehicles.

In the August incident, an off-duty California state trooper and three members of his family were killed in the San Diego area in a crash of a 2009 Lexus ES350.

Before the crash, a passenger in the car had called 911 and told dispatchers that the accelerator was stuck and the car had reached 120 mph.

As an immediate remedy, Toyota urged drivers of a range of recent models to remove driver's-side floor mats until it could issue a recall in consultation with U.S. safety regulators.

The San Diego Sheriff's Department has not completed its investigation into the off-duty trooper's crash, a spokeswoman said.

More details on the safety advisory are available at the Toyota Web site, www.toyota.com. Drivers can also call Toyota at 1-800-331-4331 or Lexus at 1-800-255-3987.