f250 89 injectors 2-3-6-7 are not polsing

so i live out on a ranch about 33 miles to the nearest city. i use my f250 89 for crossing rivers in the winter time. its kinda my life line. i tested for spark and it was working great. i did a water test to see what injectors weren't firing found that they were 2-3-6-7 all the rest are working fine, i flipped the wire from a working injector to one that doesn't and it seemed to work fine that time. so i tested for voltage there is power getting there. i believe its could be wiring because i looked at the wiring diagram and it shows that the injectors in question are wired separate to the ones that do work. i have all but given up dose any one have any ideas as to what it could be? its a f250 custom with the 5.8L engine gasoline 4WD. i desperately need my truck with summer cumming on i have 1100 acres of land that i cant manage without it. any help would be greatly appreciated thanks all.