Hi, I was driving to work today on the motorway, when my car suddenly seemed to lose power, the engine still ran and i could maintain speed, but if i slowed down the car refused to accelerate, also whilst maintaining speed it felt as if the car was mis firing, I struggled off the motorway and pulled into a housing estate, the car seemed to idle fine but when i applied the accelerator, the car would move to about 3-5 mph, but then would misfire as if it was only firing on 3 cylinders, The car is a 1998 citroen xsara, 1.8 automatic, any help would be appreciated as i have been quoted by a local garage about £75 just to look at it and tell me whats wrong. Thanks in advance Andy