Hard starting when cold
My mistake...a bad EGR valve does not cause those symptoms, I was thinking of something else (bad choke pull-off on a carb). But something may be causing your truck to run rich upon startup, wetting the plugs and causing it to run bad until it gets warm enough to dry the plugs. That is what a bad choke pull-off will do, although you do not have a choke, the symptoms are the same.