Cruise Control problems of the 2014 Dodge Grand Caravan

Using cruise control: upon hitting resume, vehicle accelerated rapidly to about 10 mph more that the expected recent cruise speed, then cruise control shut off. When I turned cruise back on, the light indicated it was active, but pressing the set button made the cruise turn back off. Only after turning off the engine completely could I get cruise to work again, but once again, upon using the resume button, rapid acceleration to at least 10mph more that last cruise speed, then cruise shut down. Vehicle is currently at dealer for diagnostics. And they just reported that they can not duplicate the problem, nor do they have a solution. I asked them to contact Chrysler engineers to see if there was a suggestion, because I do not want to go through another scary unexpected acceleration episode again. Nor do I want to have to drive from indiana to south carolina with benefit of cruise control again. Another symptom is that the dte display failed to drop below 40 after the gas fuel light came on - in fact, the farther I drove with the fuel light on, the dte even advanced to 41 and 42! almost ran out of fuel because I was relying on the dte display.