p0305

I have a 2003 s10 4wd with a 4.3! I’m getting a p0305 code which is cylinder 5 misfire! I’ve changed all plugs, wires, distributor, cap, rotor and new fuel filter! Still getting same code very rough idle and really bad fuel mileage! I am now lost at what else it could be and I don’t want to keep...

Is anyone else having this problem on 2000 Sonoma/S10 this started yesterday while driving. This seems to be a common problem, but unsure what the cause may be. If anyone has any ideas on what may be the cause it would be greatly appreciated.