I have a 2006 Chrysler 300C (imported from USA, LHD). Today I noticed engine was "running rough" and seemed to be revving itself even without the gas pedal depressed. After a mile or so of this I attempted to brake at traffic lights, but the engine suddenly began ro rev furiously. Managed to stop with great difficulty a few feet further than I expected. Whilst waiting for lights to change and without touching anything, engine suddenly revved madly again and I had great difficulty holding the car back. Managed to get to a quiet road, off engine for 10 minutes, then it was fine. Took it to my dealer who found nothing on diagnostics computer. Have since driven home (200 miles) and it is fine, but without an explanation I have lost confidence in the car.