TL*THE CONTACT OWNS A 2006 LEXUS IS350. THE CONTACT WAS DRIVING APPROXIMATELY BETWEEN 35-45 MPH WHEN THE VEHICLE ACCELERATED UP TO 90 MPH WITHOUT WARNING. THE BRAKE PEDAL WAS DEPRESSED TO THE FLOOR WITH EXTREME FORCE. THE VEHICLE FAILED TO SLOW DOWN. IMMEDIATELY,THE EMERGENCY BRAKE WAS ENGAGED AND THE VEHICLE SLOWED DOWN. THE FRONT DRIVER SIDE FLOOR MAT WAS REMOVED. AN IDENTICAL FAILURE OCCURRED ON A SEPARATE OCCASION WHICH RESULTED IN THE VEHICLE CRASHING INTO A TREE. THE CONTACT DID NOT REPORT ANY INJURIES OR STATE THAT A POLICE REPORT WAS FILED. THE MANUFACTURER WAS NOTIFIED OF THE MALFUNCTIONS AND CONFIRMED THAT THE DRIVER SIDE FLOOR MAT BE INSTALLED IN THE VEHICLE. THE AUTHORIZED DEALER RECOMMENDED THE FLOOR MAT NOT BE INSTALLED. THE CONTACT RECEIVED CONFLICTING INFORMATION FROM THE DEALER AND MANUFACTURER WITH UNCERTAINTY OF THE FLOOR MAT INSTALLATION. THE FAILURE HAS NOT RECURRED. THE FAILURE MILEAGE WAS 44,000. THE CURRENT MILEAGE WAS 65,000.