Speed Sensor problems of the 2000 Hyundai Sonata

I have had numerous problems with my vehicle, ex. Power failure, speed control sensors being replaced constantly and too much to list. My vehicle is constantly in the shop some incidents could be accident causing. I have reported to the better business bureau, and the attorney general, my next step is filing a personal lawsuit against the dealership that the sold me the vehicle. Can you please help me, I fear that my children are not safe in this vehicle.

The contact owns a 2000 Hyundai Sonata. While driving approximately 45 mph, the engine began to rev excessively high and the vehicle lunged forward unexpectedly. When the accelerator pedal was depressed, the vehicle hesitated and vibrated. In addition, the automatic transmission shifted violently into gear. There was no power response during acceleration, which resulted in the engine stalling intermittently. The warning indicator also illuminated on the instrument panel intermittently. The vehicle was taken to an authorized dealer for inspection, but they were unable to duplicate the failures. The mass damper was replaced. The vehicle was taken to an authorized dealer on six separate occasions for identical failures. The repairs consisted of a complete tune up, replacement of the "output" speed sensor, and the battery was replaced twice; however, the failures continued. The extended warranty on the vehicle expired at 60,000 miles. The vehicle has not been repaired. The failure mileage was 13,559 and current mileage was 82,505.