Rough idle and misfire?

Shorted out cylinders 4, 5, 6, no # 5 had no response. Remove spark plugs numbers two and five electrodes we’re barely worn and slightly black. Replace spark plugs with NGK Iridium spark plugs. Started engine misfire still existed. Shorted out cylinders for five and six cylinders four and five no response. I switch the coil from 6 to 4 and misfire travel to six. Continue to short out five and six one at a time sometimes I would get a response and sometimes not. At one time I shut it out five and six at the same time and there was no response oh no change connected OB to tester no trouble codes.