The plaintiff in a class-action lawsuit against Toyota owned a 2008 FJ Cruiser, similar to this, one of many vehicles the automaker is recalling.

Citing 16 deaths and hundreds of injuries allegedly caused by a defect that can cause “runaway” vehicles, a California law firm has filed a national class action suit against Toyota.

The lawsuit is the latest twist in a story the Japanese maker had hoped would go away when it announced, earlier this autumn, plans to recall nearly 4 million vehicles for a potential safety defect.

The automaker has put the blame on the design of its floor mats which, it has said, can be improperly installed and snag the accelerator pedal, making it difficult for a driver to stop the vehicle.

The problem is only caused by “out-of-position and inappropriate floor mats,” Bob Carter, head of the flagship Toyota division, said during an appearance in Detroit, last week.  The executive insisted that the National Highway Traffic Safety Administration had ruled out other potential causes, such as electronic interference with Toyota’s engine control computers, labeling talk about other possible causes “unwarranted speculation.”

But late last week, the government cautioned that it had not yet given Toyota’s powertrain systems a clean bill of health, leaving open the possibility that the floor mat problem is only one possible cause.

It has also been speculated that drivers might inadvertently be pressing down on the accelerator pedal, rather than the brake, which would help explain why some owners have reported their Toyotas speeding up when they tried to stop.

A similar problem apparently plagued Audi, federal investigators ultimately determined, when they wrapped up an investigation of the maker’s Audi 5000 sedan.  Despite widespread claims, aggressive news reporting and some unfavorable court actions, it was ultimately determined that the Audi vehicle was not plagued by some unknown electrical or mechanical gremin.  The automaker did, however, redesign the layout of its pedals to make it more difficult for motorists to slam the wrong one during an emergency.

Despite that experience, a statement by California’s McCuneWright asserted that, “neither driver error nor floormats can explain away many other frightening instances of runaway Toyotas. Until the company acknowledges the real problem and fixes it, we worry that other preventable injuries and deaths will occur.”

The firm’s suit lists 16 deaths and 243 injuries, so far.  The lead plaintiffs are both Los Angeles residents: Chris Chan Park, who owns in a 2008 FJ Cruiser, and Seong Bae Choi, who has a 2004 Camry.

It was, however, an August accident involving a California Highway Patrol Officer and his Family, claiming four lives, that brought the problem to national media attention.

“We think the lawsuit is necessary to save lives,” said McCune Wright attorney David Wright.

While Toyota officials insist they’re confident their products will eventually be cleared, the publicity is clearly a problem for the maker, which only last year became the largest-selling auto manufacturer in the world.

Toyota has been facing other problems, in recent months, including allegations by a whistle-blower, that it hid critical information from plaintiffs suing the company in regards to a separate safety issue involving vehicle rollovers.