Just to wrap it all up, I was told after I decided to get professional help that it was the diaphragm. After it was fixed, the idle speed dropped to the normal level, plus I aint seeing smoke even when flooring the engine. However, I think I've lost some acceleration power... but then I guess thats a little sacrifice so as to reduce the diesel smoke to a minimum. After everything, it seems that the true cause of the problem just coincided with my engine cleaning... kinda makes you not tinker with the vehicle for a while.

Thanks again guys!