I have a 2.0L diesel on an 11 plate. Very good car, done 86k miles and no problems until some weeks ago when starting from cold first thing the morning. It fires ok and for several seconds runs well but then develops a "misfire" and runs very lumpy. If you try an get the engine to clear by gently pressing the throttle it may run worse or even stall. After maybe 2/3 minutes the problem will apparently clear and drive on 4 cylinders but with a prnounced rattle when accelarating. As the engine warms up so the rattle will disappear. Fuel consumption and performance is good when warm/hot. If car is left for hours during the rest of the day the problem will not appear until the following morning. Left car in garage last night so it was warmer by 4 degees and problem was no where near so bad. Is there a temperature sensor that controls the cold start for example? Any other ideas please?