general problems of the 2003 Jeep Wrangler

I stopped at a red light behind a Ford expedition. When the light turned green, I lightly depressed the gas pedal and the car immediately accelerated out of control. This had never occurred before. I hit the car in front of me and was able to aggressively hit the brakes to slow down enough to slow the car and shift into neutral. The car was taken to a Jeep dealership and they kept the car for a number of days. They stated they could not find anything wrong and they blamed the incident on an after market floor mat. This would make sense to me if the accelerator was jus stuck at the current speed, but the engine kept speeding up and the tires were spinning when I was depressing the brakes. The car acted like I had the gas pedal fully depressed.

Traveling at 60-65mph vehicle cut off without warning. No lights on dash came on. Pulled out of way of other traffic and came to a complete stop. Tried starting and started right up. Mileage 77,200.