2003 Dodge Truck running rich and smoking unburnt diesel

It could be that your car is not going into closed loop once it reaches normal operating temperature. You could have a bad sensor (like coolant, O2, etc).
Check for codes.

It could also be that your air filter is glogged big time, thus asphixiating your engine resulting in your pcm enriching the fuel mixture. (Check your air filter, and replace if necessary)

Check your fuel pressure. You may have abnormally high fuel pressure.

Finally make sure your fuel injectors ain't leaking.