2009 Nissan Versa electrical system problems

Nissan versa 2009 sl ' hatchback - car accelerator was irresponsive when the car was put into drive or reverse. Regardless of how much gas pedal was pressed, the car just rolled forward at approximately 5 miles/hr and did not exceed that speed. Car's RPM did not exceed more than 1100 even after the gas pedal was pressed all the way against the floor. Finally, the car was towed and taken to the nissan dealer to diagnosis. The dealer told me that they were not able to properly diagnosed the vehicle.

I was driving south on a local highway when another vehicle pulled in front of me from a side street. I immediately swerved to the right and attempted to warn the other motorist with my horn, but it did not work. I avoided this crash, but strongly believe a working horn would have helped a lot in this situation. The horn on the vehicle usually works if you hit it in the very center of the button, but only works about 50% of the time when it is pressed on either side where the horn symbols are.