Know nothing new to mb have a 02 s55 amg it’s throwing o2 sensors, secondary air injection and exhaust gas but big issue is po208 injector circuit car is barely running sounds horrible missing like crazy I moved all injectors around and cleaned them switched coils around and put new one spark plugs in. still same so put test light in injector plug all light up so was lost so bought noid light to really rest and all lit up but 7&8 injector plugs and now I have no idea where to go from here what would cause the 7&8 injector plugs to not light up guessing open circuit or something idk new to this can some one plz help me guide me tell me what to do next

ok I unplugged the plug from the ecu with the injector wires to look for a bent prong before I tracked wires plugged it all up looked good cranked car runs perfect drove it about thirty mins and now have a clyinder 8 misfire again but 99% better than it was so confused on where to go from here