My 325i just recently started having this problem. At freeway speeds, between 65 and 70 mph, the car just stalls out, complete loss of power and the check engine light comes on. A mechanic thought that it was the computer, but, I think it could either be the 02 sensor or the fuel pump. I have replaced all the fuel system relays and it has helped to no avail. If anyone has an idea, please feel free to contribute.