I had the same problem. Extremelly rough start, noisy rattle, rough idle, and a HEAP of white smoke. Used to do it on flat ground on the odd occasion, but no where near as bad. I have had the throttle body/intake/EGR valve all cleaned out since then, as they clog up with heaps of carbon deposits, and that has since fixed it. I also had my glow plugs changed, but my mechanic said it was because of all the carbon build up. So I would be cleaning your intake system out first and that should fix it.
Here's the link for a step by step guide to clean it all..
viewtopic.php?f=13&t=8630&hilit=clean+intake