PO-300, random/multiple cylinder misfire
PO-306, cylinder 6 misfire
PO-308, cylinder 8 misfire
I have no idea what the "II" means.
I would pull those plugs and see if they are either covered in oil, or fouled. I'd imagine that you either need a tune-up, valve cover gaskets, osv plate (vaccum leak?), or all three.
You can try putting those 2 plugs in a different cylinder, as in taking the plugs on the driver's side and swapping them with the passenger side plugs and vice versa, and see if the error codes follow the plugs. If they do, then you only need to change plugs, if they don't then you either need coils or valve cover gaskets.