2011 ford fiesta power indicator light?

I have a 2011 Ford Fiesta. First owner, 24,000 miles. I drive it strictly long distance, 550 miles one way when I commute between michigan and virginia. Driving on the PA and OHIO turnpike I keep the cruise control set between 65mph and 73mph. After about 275 miles of contant running, the Wrench Warning light comes on and the Radio display shows there to be a power problem. Happened three times this last weekend. I have had a Ford dealer look at it twice and there is no history recorded on the computer. They cant get it to repeat nor can they find problems. When I stop the car and turn it off, it clears and wont show up again for another 300+ miles. Any Ideas?