i´m having a problem with sti II. no CEL codes, but the car isn´t going like it should. sometimes i get 0,9 bar seconds later i get 1,1 but acceleration is not getting better. seldom it runs like it should. sometimes it bangs at higher rpm. what is causing boost differences and banging? coil packs? usually the boost goes to 1 or 1,1 but it goes like 0,8 or so? what the f... is wrong with it? maybe someone knows?

 

is this banging out of the exhaust or the engine mate,if it out of the exhuast i would persume it is a misfire and the first thing to look at is spark plugs/coil packs mate

 

it comes from exhaust. coil packs crossed my mind also.