It could be that something has gotten passed the Fuel Filter or simply have solidified around the Fuel Feed Holes in the Fuel Injection Pump Elements.

Below is a picture of one of the Elements pulled out of a Fuel Injection Pump. {Don't pull the Element out of the Pump as it alters the amount of Fuel that the Element will put out if you don't get it back exactly in the position it came out of.}

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel