Looking at that, id start with the plugs and make sure they are gapped. Im assuming its using a single coilpack and not the coil on plug setup?

See if that helps. Gap them to 0.7mm, think they come a little wider than that, but thats what I used to gap mine at. And good luck, cause taking them out is a pain in the ass, more so on the passenger side.

I would still recommend changing the MAF if it hasnt had one for a while!