i have a 2002 wrx with 108k 3inch exhaust j-spec turbo blow off valve ect... ive been driving it with the check engine light on for about a month or so, its the o2 sensor bank 1, anyway i was driving it last night and as i was entering the highway i stepped on it alittle an noticed the car shook alittle and didnt have the power it always does. now today everytime i step on it hard it shakes and just seems like the motor isnt running at top performance when petal to floor. the car runs fine and drives fine unless you hammer on it. it never done this before think the o2 sensor would affect it? or do i have other issues? the turbo boost is fine, and the tranny shifts perfect.any help would be great!!