My sister has an 03 F-250 w/6.0. The truck skips at around 1500 to 1800 rpm at a steady speed. Does anyone know where I could get installation instructions for the injectors or possibly help me with what might be the cause of the problem? Thanks

99.9% chance you have bad injectors.
remove everything covering the valve covers, remove the valve covers, the injectors are under the covers, remove em, replace em. make sure you have some time...they are a pain to do...