No idea what this could be, I might make a video with a digital camera and post it online so people can hear it.. my dad and neighboor think my car needs a tuneup and it will need an oil change in a couple hundred miles. I was told by a mechanic its nothing serious and I should get some oil additives to clean it out. I think even if a tune up dosent fix the problem i'm going to have one done anyways cause the car seems to idle kinda rough.

 

like a knocking.. it goes away sometimes, comes back at random and goes away when I'm not giving the car gas and the noise isent as fast when i let off the gas.. when i go to accelerate again it comes back.