Gas Recirculation Valve (egr Valve) problems of the 2010 Chrysler Pt Cruiser

On Saturday morning, at about 11:40 am, the temperature was 31 degrees f, and I'd noticed the dew point was at 33 degrees, according to accu-weather. It was somewhat sunny, and there was very little frozen precipitaion floating through the air. We had just left home and drove two miles through stops and starts through local residential roads. After turning left at a stop sign after driving about 1. 5 miles, the road went into a straightaway. I gently accelerated, as I usually do. The speed control was not turned on. My wife and I shortly noticed that after the usual 30-35 mph speed, that the car continued to accelerate. I checked the speed control-off. Checked the gas pedal-swinging free. Lifted the pedal with my shoe edge-no change. Tapped the brake a few times-brake operated, but no change. As I was approaching a stop sign, I stomped on the brake with both feet until I reached about 10 mph. At that point I slipped the transmission into neutral and switched off the engine. The car stopped. I got out and checked the gas pedal and floor mat-both were clear. When I tried to restart the engine, it started, and then slowed, then sputtered and finally quit. After quitting it would not restart. I called chryser warranty service for a tow. The towing service was delayed. We waited about an hour and 15 minutes, checked the eta of the tow truck when told it might be a couple of more hours, I retried the ignition, and that time the engine restarted as if nothing had happened. I drove about a mile to a nearby gas station (to wait for the tow in a safe place) with no incident. The dealer could find no problem when inspecting the following Monday. They drove 19 miles, no problem. No fault codes or TSB's. Cable not frayed. Throttle blade and gas pedal not binding. I suggest that it is possible that icing could have occured around the throttle plate, since the air was near the dew point on a hardly warm engine. After the engine sat over an hour, the ice could melted.