On my new to me 2011 RT, I the spark plug/coil cover pulled a Harley on a ride the other day. I did notice a couple of times where there was a slight miss while accelerating. I find the stick coil backing off the spark plug when the bike warms up. When cool it seems to be nice and tight. The coil backed out so far I am not sure it was even firing the plug. Anyway a new cover has arrived but it doesn't seem right that the coil would back off the plug.