Car Accelerates On Its Own problems of the 2000 Nissan Pathfinder

I have had two incidents of sudden unintended acceleration while applying the brake at low speeds. With foot on brake rear tires spun and when placed in neutral engine reved to 4500 rmps for about 5 seconds then returned to normal. Second incident resulted in vehicle going through red light at intersection with a near collision with another vehicle. Vehicle inspected by dealer who claims they cannot "duplicate problem. " consumer rep. For Nissan said that they would do nothing else unless the auto is in an accident.