P304 code Headscratcher PLEASE HELP!!
 

Someone please help me!!

I have an 08 tC manual with approx 130,000 miles
Mods(if you want to call them that): Throttle spacer and short air intake with K&N.

So recently when I come to a creep or complete stop then accelerate. The car loses power, sputters and shutters with the CEL flashing(less pickup than a model T ford). Eventually it will level out and power restores. This is intermittent and doesn't seem to have a specific pattern. Other than it only happens when I stop and accelerate. This used to happen every once and awhile and now it happens so much it is almost undriveable. Also the car has a rough idle that comes and goes as well. Reads that it's a misfire detected in cylinder 4 (P304 trouble code). There are several cause of problems for this code but I been striking out.

So here's what I've replaced and or switched around to rule out easy stuff like hoses under the hood, no vacuum leaks that I could identify BTW

*Replaced the PCV and cleaned the MAF(assuming a faulty MAF would cause all cylinders to misfire), no change.
*Replaced gas cap, no change.
*Swapped coils and fuel injectors around and still says cylinder 4 misfire though I've switched each of them to different cylinders.
*Replaced Cylinder 4 spark plug, no change.
*Replaced Vapor canister purge valve solenoid(under the hood attached to intake), no change.

So the only thing I can think of is the MAF but it only reads a cylinder 4 misfire and not all cylinders. So I'm inclined to think it's another issue that I'm unaware of. I've spent enough money on parts I didn't need so If someone could please help that would be awesome! I'm hoping that someone has the magic answer and I smack my forehead and say "why didn't I think of that".

Fingers crossed!