Engine Noise problems of the 2008 Ford Taurus

I was entering I 70 east in columbus ohio off the james road exit, while attempting to merge into the outside lane. I sped up to adjust my speed, as a vehicle was in the same lane. When I accelerated, the car automatically took over and suddenly accelerated and revved up high and fast. My first reaction was to hit the brakes, I did, but the brakes would not depress or brake. I was trying to think of everything to do and monitor the cars around me, as well. I tried holding down the brakes hard and taking off while the car went flying by two exits, I knew I would not be able to exit because I couldn't stop. I continued with trying to locate the flasher and thinking about hitting the emergency brake but, I didn't because I was unsure whether it would come to a quick stop. I kept pushing down and up on the brake pedal. Suddenly, the revving began to settle down (a fast downward revving sound) and I was able to brake the car. I was unsure whether to pull over so I decided to continue to my destination which was only 3 exits away. I parked and looked at the car and especially the area near my feet, there was nothing interfering with the brakes or the accelerator. I panicked all the way home, not knowing what would happen so I stayed off the freeway, believing the freeway speed would cause a similar issue. As soon as I got home, I researched the issue and found some similar instances with the same make and model. I will call the dealer tomorrow. I had a previous experience with the transmission stopping on the freeway and disengaging while driving and when I stopped. When I would pull over and switch the gears, the car would make a loud dropping sound. And it would be difficulty to switch gears. The car shifts at times and kicks back. The dealer replaced a sensor but, it has not resolved the issue completely. I've taken it back and they found nothing. I hope they will find something, as I am afraid to drive this car after tonights experience.