Originally Posted by Larry Delor

I would think that a contributing factor to your truck running better when it is hot than at start up, is because everything is fairly sloppy when it is cold and therefore compression is a little reduced. From what I understand, the slop is necessary, because of the extreme temps in the combustion chamber (heat make the metal expand).

ok ok, I know "slop" isn't a technical term, and it's not really slop, it's more generous tolerances.