check engine light appears when car goes into fail safe

On Saturday, June 11, 2016, I was driving home from a town 60 miles away. Approximately 20 miles from home my cruise control disengaged and went into fail safe mode. I went from 80 mph down to 65 mph. Once again I had no power using the accelerator. I had no place to pull over without affecting the flow of traffic. So I continued to drive at 65 mph. Shortly afterwards, the engine symbol light came on. It is still on. I will be making an appointment this time. Hopefully they will be able to duplicate the fail safe this time. This has become a serious safety problem to say the least. It's dangerous due to you not being able to maintain the appropriate speed to keep up with the flow of traffic. Once I got home I had to stop a traffic light. Once I was able to proceed I pressed the accelerator I had minimum power to drive the car less than 3 blocks. Does anyone have a true answer as to what causes this? Also is there a true fix for this without spending a bunch of money on troubleshooting at the repair shop.