Ok so besides intercooler condensation causing misfires this is the #1 reason for misfires on this engine. Any misfires on this engine has great potential to damage the catalyst and should not be taken lightly. As many know by now boosted engines are hard on the plugs be it iridium platinum whatever and you may find the need for new plugs by 50k miles. More so now as many are coming in with carbon tracking as this one had. In this video I walk you through the procedure to change out plugs on these engines with the revised plugs, gap specs and TSB that have all come out recently. I hope this helps.