Im having a few probs with my MY98 Sti4, it idles funnily, sometimes nearly stalling and now its started hitting the boost cut under heavy load. I have my theories whats up with it but Im not that sure. I think it might either be the MAF sensor or that fact that I might have a small hole or crack in one of the boost pipes??? Any ideas as its really doing my head in!! The lastest thing is when Im putting my foot down when it gets to about 4500 rpm in either 4th of 5th the revs move up and down between 4500 and 5000 as if Im revving it, any ideas?

 

Yep it sounds like the maf sensor,have you got an induction kit.

 

Yep, K&N and your old Hiper Ti