Fault coil? Bad fuel filter? Bad oil?

[krystalized_jdm]

Seem to be having issues with my engine.

From what I know. I got the coils replaced approx a yearish? ago. (Not 100% if they were used or new. Assuming they're new from the price I paid. I also didnt do the work myself)

Basically. My car has a....rumble sound to it? It sounds as if a cylinder isn't firing.

I've looked around and I've seen it may be my MAF sensor having extra air coming in. I tightened intake bolts and hose clamps.

I was also told to check coils which I'm not 100% sure how to do.

I can upload a video on how it sounds. Maybe it'll give more insight.

Any suggestions on what it may be or what I should check?

Also, does anyone know if coilpacks are cylinder specific? (hoping to just order 1 and find the dead one if thats the issue)

[DarkCaporaL]

Coils are all the same so you can just get one if you need to.

To get to them you need to remove the valve cover (around 6-8 allen screws) first. At this point you can either remove them one at the time by undoing the 4 bolts keeping them secured (6 coils x 4 = 24 screws total), OR you can remove the bracing plate that holds all of them down which is about 6 screws if I remember (makes it easier to work off the car).

EDIT: Just noticed this is the GTS section, my post relates to the RB26 so this may not apply 100% for coils removal....they should all still be the same though.