no acceleration when pushing gas pedal while driving down

My daughter was driving home from school and had to coast to the side of the road on a major interstate because her car lost the ability to accelerate. The gas pedal was completely pressed to floor. She turned the car off and restarted the car. The same problem repeated itself for the next several miles... all the way to the Ford Dealership. We were told they had no idea what the problem could be. They later said the adjusted the computer for the fuel throttle???? the next morning the problem returned. There is no way my high school daughter can safely drive this car. We purchase this Ford Edge brand new and has less than 5,000 miles.