So I am driving down the road in my 2013 Prius C-3, 60mph, cruise control set and everything is fine. I turned off the cruise control with the button on the end of the lever and the gas engine dies. I push the gas petal down and it feels like the regenerative brakes are slowing me down. At about 20 mph the gas engine starts and I resume 60 mph. I tried to re-create the problem with no success. Any ideas??? Oh and no warning lights, no check engine light.