Guys ive had this issue for a good year,  ONCE the truck gets warm it acts Real missy at idle in Park, and any unloaded rpm range. ONCE i. Put a load on the engine it doesn't mess up. Does not mess up when first start either.   Changed injectors 3 times no change, New vp44 2 months ago. No change 

 

No codes.    Nothing seeems out of place. 

Did you test the injectors to see the spray pattern or pop pressures?

 

Do you have air in your fuel? You might hook up a piece of clear tubing and loop it on the windshield and see if there is any air bubbles.

This sounds similar to my issue, although I do not know if it goes away under a load. How bad is it missing? It it making the motor lope or just one cylinder seem to be messing up?