Hi all. I have this slight problem with my Citroen AX 1.5 diesel. When it is idling at normal operating temperature, it feels like it is idling too slow, i.e. it shakes the car to pieces. Then sometimes all of a sudden there is a slight click comes from the engine somewhere and it will start idling at the correct speed. I'm guessing it might be something to do with the diesel pump but i'm not sure. Any ideas anyone?