Hmm, If you have changed the plugs and it runs fine at low boost but not high, coil packs and leads next.
See if you can get a single coil pack and you can swap it one at a time so you know which one is knackered.
Did you make sure the gaps on the new plugs were set right? They are a cooler running spec as well i presume?
See if you can get a single coil pack and you can swap it one at a time so you know which one is knackered.
Did you make sure the gaps on the new plugs were set right? They are a cooler running spec as well i presume?