I was driving my 2003 Ford Mondeo diesel estate yesterday and I was about to accelerate to overtake a lorry at 60mph when I lost all power and my glow plug indicator on the dash started to flash. Then the engine just died. After restarting my car straight afterwards it seemed to be ok, but after a short while I accelerated again at 70 mph and my glow plug started to flash again. I pulled into a layby and turned off the car and restarted it again, and had no other problems. Can you suggest anything?