isnt that coil on plug? if so, its almost definitely a coil
easy way to tell..
goto cyl 8, unplug injector, does miss get worse? if not, not an injector
if wires:
lift up wire, can you hear spark jumping? does the misfire get worse?
If you hear no spark jumping, follow that wire to the coil pack, lift it there, do you hear/see arcing? if so, bad wire, if not bad coil
if coil on plug, unplug coil, does misfire get worse? if not, bad coil