You may remember our cover story this past spring about unexpected acceleration—and other strange automotive behavior—bedeviling owners of the Toyota Prius ("Wheelzebub," April 22). Back then, the amusingly patronizing response from a Toyota spokesperson was: "People are so under stress right now..." In other words: It's the driver's fault—they don't know what pedal their foot's on. Five months later, Toyota issued the biggest recall in its history—3.8 million vehicles, including all Priuses made between 2004 and 2009. But Toyota seems to be trying to have it both ways. The problem, everyone agrees, is with the drivers' floor mats. These have the unfortunate habit of entrapping the gas pedal, causing the accelerator to "get stuck in the wide-open position," as Toyota puts it. That's when drivers suddenly find themselves perched on a patch of gravel in the middle of a river and don't know how it happened. Recently, Toyota started sending letters to owners of the Prius—as well as numerous other affected Toyota and Lexus models—notifying them of the problem and the recall. But in the letter, Toyota claimed that "no defect exists" in its vehicles. Toyota still seems to be blaming the driver, saying that the problem occurs only when the owner is using a floor mat that's not "compatible" with the vehicle, or hasn't "properly secured" the mat. That drew a strong rebuke from the National Highway Traffic Safety Administration, which called Toyota's claim "inaccurate and misleading." The NHTSA insists that there's an "underlying defect...which is related to accelerator and floor pan design" and that Toyota's got to fix it. Meanwhile, the agency says the most immediate way to avoid the risk of having your Prius slam into a line of parked cars at the mall is simply to remove the driver-side floor mat. But do so carefully. If you screw up anything else in that car, Toyota's really going to lose patience with you.