ive fitted a 280bhp chip to my 1994 wrx wagon problem is at around 4500rpm the car starts hesitating and spluttering was suggested maybe coil packs or plugs have replaced them both and the car still does it (2 of the coil packs did have cracks in them) any one any ideas ??????? it seems to take half throttle no problems then full throttle starts backfire vai exhaust and runs really bad

 

Is the chip deffo for a wagon as most of the chips are for the saloon td05 turbo where as your wagon will be the td04 turbo.Just to clarify first if right could be spark plugs checked the gap ?

Mark

 

ye the chip was mapped etc for the wagon i put in new denso spark plugs is there better ones to try ??????