Today my 2014 Volt with 114K miles showed it's first ever problem. When I selected "Drive" and pressed the accelerator to move out, it jumped ahead like I had pressed the pedal to the floor! I had to jam on the brake to get it under control. After that it seemed to run like an IC engined car with the choke stuck on fast idle. At every traffic light or stop sign it wanted to creep ahead strongly requiring a firm press on the brake to keep it stopped. It took a very light touch on the throttle to drive in city traffic. The car ran at 35 mph in "Drive" without pressing the pedal. It is like the "Sport" driving mode on steroids! The power (KW) indicator in the driver's display showed no power regeneration when the brake was applied. It felt like the friction brakes only were working. Any thoughts on what might have happened? Does it need a service appointment to reprogram the throttle response? There were no warning codes and otherwise the car ran normally.