I have AN 06 Zafira life, an in need of help?

My Zafira all of a sudden keeps cutting out, just stops dead, take the key out put it back in an it works, then does the same again, the engine management light keeps coming on so ive taken it to 4 garages now its been on the tech 2 machine an normal reader an its showing no codes saying there isnt any fault with the car at all, can anyone help a really stressed Zafira owner