05 Cts cylinder misfire
 

I've been at this for weeks. It started out as a bad alternator. I replace the alternator and the the car wouldn't start. I found the starter was bad so I replaced that. After reading codes it told me the crankshaft position sensor was bad so I changed that and cleared that code then I got p0300-301,303 305. I changed all the plugs and coils. I then got the same codes along with the mass air flow sensor. I cleaned that and got that code cleared. Now I still have the same cylinder codes. I'm about ready to pull my hair out. HELP