Mine is a 2012 Megane 1.5 dci, one day after we had lots of rain the car just started to accelerate away by its self braking did no good or dipping the clutch just let the revs run too high , luckily enough I was going up a fairly long steep hill in light traffic , I managed with foot and hand brake to turn into a side road that I knew had a large layby, I turned in and stopped the engine, much steam comming from the brakes, I waited 5 min re started no probs, must have been water got into its brain, Its never happened since although sometimes between 68 and above the engine cuts out for a milli second and then carries on as normal but never below that speed, I think its something linked to the speed limiter, Ive pot it down to ****y French electronics.