I recently had my window down (this may have been there all along) when I accelerate gently I hear this noise but when I get off the gas you do not hear it. I was driving under 30mph. Only when giving it the gas it sounded like a car like ping when the fuel was bad. I use 87 octane and the fuel is fresh. When you lift the hood you do not hear anything like a pully going bad. I have 110,000 on the vehicle. Recently had a new Gates belt put on the vehicle. Any idea or suggestions it appears not to be super urgent. Is this something on many 1.8L ? Not running hot or any obvious alerts. I have taken good care of this 2014.