2001 F250 4x4 crewcab 7.3
I just replaced the valve cover gasket and wiring kit on the driver side. I ohmed out the wires and they seem to be good. Injector 2 has oil coming out of the exhaust tube but 4, 6, & 8 does not. I do an injector fire test and all injectors fire individually. What could be the cause of them 3 injectors not exhausting oil?