i disconnected the battery for 2 hours note the radio security code thus resetting the ecu any mechanic recommends doing this every 3 months on a mk4 fiesta encore and most cars apart from hyandai daewoo .
especially after fitting a 12 quid patent idle control valve off ebay .
this sorted my over revving / stalling encore
Chris LUKE, June 2010
Mine does just the same. I was told to clean the vent pipes that eminate from the oil filler cap and replace the filler cap. Unfortunately this did not work on mine but may do on yours. Did you ever find another answer?