Yeah so the car has been getting looked at for a few days now, we have adjusted the plugs, checked all intake piping, read the
ECU for any codes (none there) and the problem remained.
Tried a different AFM and the problem was even worse. Went back to the original after a good cleaning and it's okay now apparently, with a tiny flat spot up top. Does cleaning the AFM last for long before it screws up again? They are a $500+ part from Subaru brand new.
I am contemplating having ASG take a look at the tune to make sure everything is alright as well as running around on a dodgy AFM could spell disaster.
Ideally it would be better to invest that $500 into an
ECU which doesn't rely on the AFM as it appears that even the AFM's on the newer rexies are not so tolerant with oiled pod filters, even if they are oiled very lightly. Sooner or later they die.