whats your fuel filter like you may off sucked up some poop when giving it beans check the state off it and c from thier
could be fueling but it should do it all the time when on boost not intermitent
you might have a very tiny split in vac or boost pipe that opens up when giving it beans
the plugs are the right ones for the car as i was told i could fit platuim ones in my old series 1 and it pinked like it was in fashion lol