Hi. My Kia Grand Carnival 2006 recently had the alternator replaced (brake and battery light had been on for a few days and then other lights came on and just managed to get the car home). Apparently there was a light oil leak that had been there for some time (despite no wet oil drops on the driveway) that had completely covered the alternator in oil hence new alternator was fitted. The car ran well for a couple of days, however now the check engine light is flashing and the car is idling very roughly at traffic lights etc. (to a point where it feels as though it will stop). What could the problem be?