4.0 started running rough, I changed spark plugs, still runs rough.

Plugs were long overdue. New plugs are the same # that I took out. When I disconect wire to fuel injector on # 1 cylinder, it makes no difference in how the motor sounds. When I disconect #2, I can tell a difference in the way it sounds. There was some codes, I cleared them after replacing plugs. They were 300, 301, 305, 340, 442, 455. Service engine light has been on a long time. Engine light is not on now, but the motor idols a little rough and when you start to drive it, it shakes bad. I think #1 plug is not getting fire to it. I took # 1 plug out, and it was clean, #2 & 3 had some black stuff built up on them.