Hi, I'm new to this, I have a 2010 Subaru Impreza 2.5i Premium. Well it's been sitting for almost a year bc the number one cylinder side sparkplug got loose and shot out messing up the threads so bad that the spark plug wont tighten but I fix that put the head back on and now I have a knocking sound coming from that side and it never knocked before that, it's a new motor only 2years old. I'm lost and need help.