hi there av got a mk1 mondeo v6 it has this problem that to me sounds like it is over fueling the exhaust stinks, like runing very rich wont idle when this problem is not there.but when it does occur has no power uses loads of fuel. the exhausts are normally claer are all sooted up to the extent that the bumper is covered in soot to any ideas. could this b a map sensor,or and when it runs rough the fan is permantley on even though the car is not warm thanx.