guys sorry po for my late reply, ganun pa din po van ko tuwing umaga. Now to answer your post one by one:
1.) Make and Model - 4m40 / '96 Spacegear 4wd 80k mileage
2.) Napansin ko lang na may parang film ng oil sa exhaust manifold connecting dun sa engine block, pero di naman nagbabawas.
3.) May nagsabi sa akin na mechanic na baka daw nozzle tip, but not sure ako dun.
4.) Pwede yung sinabi ni dieseldude pero 80k pa lang yung van ko and wala kong ibang problems except for that cold start with white smoke.

This could be an injection pump problem.......white smoke with rough idle during cold start is very common on 4M40s.