Ok, I've been having this problem for a while now.

Last year I rebuilt my motor. New pistons 82.5mm, shotpeened rods, new bearings, front/rear seal, balanced everything, block deck machined .35mm, and head machined .5mm. I also put in new bearing here and there, and a GSR water pump. Just recently I put a new adjustable fuel pressure regulator in a tuned it about 5psi higher then stock. I also just put a new Modine radiator, and a Main fuel relay.

Now, my car starts up just fine when its cold, but lately it has been idling rough like its only running on 3 cylinders when cold. Once warm it runs fine for a while and then idles up and the check engine light comes on. I checked the code and it says code 6 "High coolant temp" but the gauge says its running at normal temp.
After its warmed up, if I turn it off and then go to start it back up, it just turns over like its flooded and then after a while it might start (all the while with my accelerator floored).

 

come on guys.. someone has to have some ideas