1997 model with 4.6. Running extremely rough, no power, pinging. Shows lean code for both banks but no actual misfire code. I've checked all vacuum lines, intake gaskets, pcv valves, fuel pressure. Full tune up with plugs, wires, fuel filter, air filter, cleaned MAF. I did have it running and one by one pulled injector connectors. Some made a difference in running others not so much. Clogged injectors? I did check resistance on them and all were almost identical readings and you can hear them all clicking. Just kind of at a loss here on what to check or do next. Just bought this rig and want to get it right!