Ive been having some white/blue smoke under heavy throttle lately, it use to be just at low rpm 900-1100. When it would happen between 900-1100 rpm the truck would shake "miss", I think I have narrowed it down to the #8 injector. If I look at my cylinder rotaionnal values with A.E. the #8 is seeing 3-4%, while the other 7 never see more then 1% usually they stay at 0%. Also this is an intermediate problem, sometimes my truck runs great, others times not. A change in outside temp seems to make a differance, lately in CT it could be below freezing or up to 70deg. It seems to act up the most when the temp changes.