I've owned this stupid taurus since August of last year. Its always had a misfire at idle (flashing CEL) Tried several inexpensive repairs nothing worked. Replaced spark plugs and coil pack=nothing. Took it into the ford dealer a few months ago they said that It needed a major engine repair to the tune of $3600. They gave me the codes of P0305 and P0316. So the other day I was driving and put the air conditioning on and the car idled fine and actually ran much better. Does this problem have something to do with the air conditioning?? By the way, I drive a 2002 Taurus SES with duratec engine.