more than likely you have several of the issues mentioned above. the problem centers around the bad quality of diesel fuel available today.poor quality diesel(every where today)with excessive moisture(water) and other particulates or contaminates are extremely hard on your injectors and cause injector failure and injection pump failure.the lift pump and fuel filter are inadequate for the poor quality of fuel available today. the cure for the future is a filtering system designed to remove excessive air, water and other contaminates and consistent lift pressure. AIR DOG is one of the most effective but there are others. Air Dog approximately $500.00. If your injectors are bad you will need to replace all injectors and feed tubes. $1600.00 - $2400.00, use cummins parts only. then purchase Air Dog system and I recommend using Lucas Fuel Additive to help with lubrication of the injection pump since lead has been removed from fuel. hope this helps