Hi,
Ive had my X MR for just over a year from new and i fitted the Cobb Accessport around 6 months ago and ran the Stage 1 map. It is now throwing up the P0302 code only when the stage 1 map is in. If i revert back to stock it does not happen. I realize its a misfire with the cylinder 2 but i dont understand why it only throws up the code when i have the stage 1 map in?
Car is stock apart from this
Any ideas

 

Pullout the spark plugs and inspect them for damage. Damaged spark plugs may have a harder time firing under higher pressure so it may run okay with the stock map but under higher boost of the Stage 1, it may misfire.