1997 Dodge Ram P0305 Code

I have a 97 ram 1500 4x4 with a 360, The truck had the heads rebuilt about 50,000 miles ago as well as the trans, and from what i can tell the computer on the firewall looks to have been replaced recently also. It has been running rough and it shows a P0305 code, which says cylinder 5 misfire. I just put brand new plugs in it and also a cap and rotor, I also pulled the bed off and found that the vent hose on the sending unit that goes to the "charcoal box" was unhooked(so I replaced the line and kooked it up) the fuel filter in the tank appeared to look good. I wonder is it maybe the wires or injectors or even as simple as the coil. or could it be worse and it already fried a valve before i bought the thing