silver 6.0 doesnt sound like a bad FICM or it woudl do it all the time. Possibly a couple bad injectors or low fuel pressure, have you changed your fuel filters in a while?
Let me ask you this, have you recently changed the oil? OR changed brands of oil. I had this problem and it did it for about 2 weeks after I changed oil brands from Ford Powerstroke to Rotella. Both are 15-40 but for some reason my truck didnt like the Rotella for a couple weeks. I have used Ford Powerstroke oil in mine since new but it had gotten up to 3.50/quart and so I changed to Rotella as I can get it for about 2.65 per quart and even less when on sale. I think it has something to do with oil viscosity as when warmed up it is probably a little thinner and the injectors seem to work better. Just a theory. I also changed both fuel filters at this same time so not sure if I had a little air in my lines, or if I had a fuel pressure issue either. It has cleared up and completely stopped.
SOFLASMOKER = it sounds like you have an EGR issue or worse yet, head gasket problem. Overheating, puking coolant, white smoke, sounds like you better get that fixed right away, you are going to eat up some injectors pumping water and when you floor it/WOT you are increasing the cylinder pressure which is probably causing the excessive smoke and roughness as you are getting all kinds of strange pressures in the engine and it is going bonkers trying to figure out what to do with itself.