As long as the glow plug is still threaded in, I don't see how it would run rough permanently. The relay only stays on 2 min, and then none of them do anything. It doesn't sound to me like that is the Ops issue.
One other quick thing that you can do without any fancy tools is unplug the ICP sensor on the driver's side High Pressure Oil rail. It will then go to a default value, and if it runs OK unplugged, then the sensor is the issue.