Had a similar problem myselfwhich turned out to be the injector leak off pipes leaking air. They are the small rubber pipes linking all the injectors, & there is a blanking plug on the last one. Change them all , but get a genuine blank from citroen cos the aftermarket ones only last 5 mins. Try priming the hand primer befor starting , if this improves it its almost certainly an air leak in the fuel system, if not check all the heater plugs , just one down will make it poor starting. Hope this helps