2004 Ford F250 Problem with f250 shutting down the motor

I recently bought a used ford f-250 with relatively low miles. The truck runs great and rides great and appears to be clean. The only problem that I have had, and seems to be rather serious, is that the water separation light and the glow plug light will illuminate when ever I hit a pot hole or bump in the road and it will either kill the engine or make very sluggish and almost stall out. Need some ideas of where to start.

Thanks,