engine fault

Hapy New Year! Lets get down to it. 2010 Gti, 69.9K miles, No mods (except R8 coils and K&N drop in air filter) Just changed the plugs, coils, and oil about 4K ago after I seafoamed the car. And that fixed my misfire code... for a few thousand miles. But it came back with a vengeance, and...