1990 MM 4G64 with 225,000 miles. I am chasing a rough idle and poor drivability. Pulled all four injectors and sent them off to be cleaned and flow tested. Before and after the cleaning, the number four injector was not flowing. I placed all four injectors in plastic bottles and cranked the engine. 1,2,3 were all equal but 4 was dry.
at this point im concerned about a wiring harness issue. What should i do?