Engine cuts out?

Hi please please somebody help ????? I have a vauxhall zafira 1.8 elegance auto x reg , I had power issues and by renewing air mass it run like a dream for three weeks , then the car started to mss fire , so renewed Ar mass again and coil pack , then the car would just cut out , wouldn't restart until about 30 mins later have since renewed coolant sensr and crank case sensor , also ran a new earth for the air mass , had the ecu sent away for testing twice unable to fault ran the car on the drive for two hours idling all ok then drove down the road next day , and the engine cut out waited 20 mins then it started with the engine management light up , am nw at my wits end please please any solutions