ICP is injection control pressure sensor, cps is your cam position sensor. When your cam position sensor goes bad, it will shut the truck down, I guess in theroy you could have a deterioating one causing a lack of power concern, but the likelyhood of that is not very high. 99.9 time out of a 100, your truck will shut down on you randomly. Make sure you invest in a nice long pry bar or screw driver and a 6 point wrench, I say again, a 6 point wrench. The 12 point wrenches tend to round off that bolt.
I believe there is a TSB on the water light coming on when there is no water, and it has been a while, but you replace the element at the bottom of the filter housing. I dont think it is expensive. See your local ford dealer.
The fuel heater element causing the truck to shut down is again, highly unlikely, I personally have not ever had that issue with a customers truck before, I would look into replacing your cam sensor, and doing that heater/sensor element in your fuel bowl.
I think you have 2 seperate and unrelated problems going on here.
You may also look into replace the cam sensor with a better one, I beleive the blue sensor from interntional had less isssues then the ford one, you may want to search the forums on that one, but I know there was a rumor flying around about a more robust cam sensor to install in the trucks.