I just pulled the codes off the computer in my truck. there is three of them only two that I am worried about right now. i keep getting a P0306 which is a misfire on cylinder 6 and i also got a P0305 which is misfire on cylinder 5. i have replaced the plugs, wires, and the coil pack and i am still getting these codes. soes anyone have any ideas what else it could be?

the other code that i got was P0455 which is a emission system leak (Large). i think this is from when my exhust fell off on me. i have that fixed now so that is not a problem.

any ideas are greately appericated and thank you in advance.