WASHINGTON - The 911 call was from a frantic passenger, trapped with family members in a runaway vehicle barreling down a California highway with a stuck accelerator and no brakes.

The call ended with someone telling people in the car to hold on and pray, followed by a woman's scream.

The high-speed crash near San Diego in August, involving an out-of-control Lexus ES 350 that killed four members of a family, led Toyota Motor Corp. on Tuesday to issue its largest-ever U.S. recall, involving 3.8 million vehicles.

The recall is intended to address problems with a removable floor mat that could cause accelerators to get stuck and lead to a crash.

Toyota and the government warned owners Tuesday to remove the mats from their vehicles until the Japanese automaker could find a way to fix the potential safety hazard. The recall will involve popular models such as the Toyota Camry, the top-selling passenger car in America, and the Toyota Prius, the best-selling gas-electric hybrid.

Toyota said it was still working with officials with the National Highway Traffic Safety Administration to find a remedy and said owners could be notified about the recall as early as next week. Toyota spokesman Irv Miller said until the company finds a fix, owners should simply take out the removable floor mat on the driver's side and not replace it.

"A stuck open accelerator pedal may result in very high vehicle speeds and make it difficult to stop a vehicle, which could cause a crash, serious injury or death," Miller said.

The recall will affect 2007-10 model year Toyota Camry, 2005-10 Toyota Avalon, 2004-09 Toyota Prius, 2005-10 Toyota Tacoma, 2007-10 Toyota Tundra, 2007-10 Lexus ES 350 and 2006-10 Lexus IS 250 and IS 350 vehicles.

Toyota's previously largest U.S. recall was about 900,000 vehicles in 2005 to fix a steering issue. The company declined to say how many complaints it had received about the accelerator issue.

NHTSA said it had received reports of 102 incidents in which the accelerator may have become stuck on the Toyota vehicles involved. It was unclear how many led to crashes.

"This is an urgent matter," Transportation Secretary Ray LaHood said in a statement. "For everyone's sake, we strongly urge owners of these vehicles to remove mats or other obstacles that could lead to unintended acceleration."

Toyota warned owners that if they think their vehicle is accelerating out of control, they should check to see whether their floor mat is under the pedal. If a driver can't remove the floor mat, Toyota advises drivers to step on the brake pedal with both feet until the vehicle slows and then try to put it into neutral and switch the ignition to accessory power.

For vehicles with engine start/stop buttons, Toyota said the engine can be shut off by holding the button down for three seconds.

In the August incident in Santee, Calif., the fiery crash of the Lexus killed California Highway Patrol Officer Mark Saylor, 45, and three family members on State Route 125. The vehicle was traveling at more than 120 mph when it launched off an embankment, rolled several times and burst into flames.

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, something that could have snared or covered the accelerator pedal.

Toyota spokesman John Hanson said the final report had not yet been submitted in the California case.

"We don't know what the actual cause was of that accident other than preliminary reports that have been published so it's impossible for us to comment on that particular incident," Hanson said.

In mid-September, Toyota ordered 1,400 Toyota and Lexus dealers nationwide to ensure that each new, used and loaner vehicle had the proper floor mats and that the mats were properly secured.

In September 2007, Toyota recalled an accessory all-weather floor mat sold for use in some 2007 and 2008 model year Lexus ES 350 and Toyota Camry vehicles because of similar problems.

For more information, consumers can contact the National Highway Traffic Safety Administration's hot line at (888) 327-4236, Toyota at (800) 331-4331 or Lexus at (800) 255-3987.