I looked a little farther into this and i have narrowed it down to 2 things either a intake heater or, the fuel heater i replaced the fuel heater relay and it did not really change much, if you guys have any suggestion please let me know. i would really like to get this taken care of so i dont mess anything else up.

 

Just a question, are your batteries good? are you using anti-gel additives? Power Service Diesel 911 (red bottle) may help

 

How about the year, model, and a little more info......