I have a 2000 ford f-450 7.3 to start out I just pulled the motor out for the same problem and put a diff one in it starts and idles fine going a mile or two down the road and it will start losing power and smoking white smoke then it will not go faster then 20mph but most of the time it wont go that fast I have swap the drive module that's in the driver fender and the fuel pump with another truck I have I have no clue what else to do. please help me