does it start to miss fire when it hits boost and then goes alright near rev limiter, trust me u can bearly see the crack if its coil packs, the other thing is that it could be shit fuel i bought some fuel in batemans bay and it was a independent shell station i whack some octane booster and then it ran alright.just a questoin did start to run crap after u filled it up and r u using 98 octane fuel