Well recently ive been hearing a noise when I idle. It sounds like pinging but im not sure. Its definietly coming from the engine, and it sounds like rattling noise. But the thing is it goes away when I rev it. It also isnt constant either cause it will go away and can only be heard at times. Its just with this tank of gas, I hear it more often than Im comfortable with. I was curious if it was possible with no load. Or i might have a different problem like a spun bearing?? Do they sound a like? Any help would be great.