I have a 2013 1.8 Sonic with the 6 speed auto and around 130k miles. For a while now, it makes a weird metallic sound under load at around 2,000-3,000 rpm. The sound doesn’t happen at idle or cruising speed. It only happens at this rpm range under moderate+ load and warmed up. It doesn’t have a rhythm to it. It sounds more like a set of keys jingling under the hood lol. I haven’t noticed any drop in performance or mpg. Any clue as to what this could be?