Please help. My s40 D2 (1.6 115hp) is acting really weird lately. When start-up, engine stutters when revving (car in motion or not) and its hard to launch smoothly. Lately 'Engine performance reduced' popped up twice having the engine in limp mode and low power. The stuttering seems to go away when engine temperature rises. P.S. current average consumption is 7.3 The mechanic connected OBD scanner and noticed all 4 cylinders injectors offset something.. Thus we concluded that the injectors nozzles must be refurbished at a professional shop. Any thoughts?

P.S when it is stuttering it smokes a bits