My BMW 318i will not start. When I was entering the autobahn from an exit I put the car in 4 gear and began accelerating. The engine died abruptly (no jerking, jolting, sputtering) just cut off, as if I turned the key off. It will not start up again. The current mechanic who is working on it for about a week ran out of ideas. Things tested are: fuel pump, ecm, crank/cam position sensor, relays. Now I do no know if my car has a imobilization system, but I had heard that it may cause an issue like this. Please help. Thank You.