I have a 2014 eco boost focus. it has developed a weird issue where at times the engine will carry on running when the key is removed. Sometimes its just for a few seconds and sometimes for longer, up to a minute or so. When it does run on the dash, radio, lights etc all go off but engine is still running. You can even put it in gear and drive off.  It even started up once without the key in the ignition when the clutch was pressed. It doesn't do it all the time and is random when it does do it. Maybe unrelated but the start/stop hardly works anymore compared to working all the time when i got the car 3 years ago. I have reset the battery (fog light,hazard light sequence) but no different. I read the start/stop can stop working if the battery is older and not reaching a full charge or over 80% so could this be a related problem. I cannot find any related articles or similar problems posted. Any help would be appreciated.

Did you ever get this sorted. I’ve had mine a month 2014 and experiencing this issue