It must be something with the fuel pressure or something because ill shut off the car and it will be humming pretty loud then ill take off the gas cap and a lot of air will come out and the humming will stop. I just had my fuel filter replaced about a week and a half ago. Is there anything I can do to stop this noise or is it even bad? Please help, thanks

 

I don't think that humming is a sign of trouble. After you turn off the engine put your ear next to the fuel filler cap, to see if that is the source of the sound. If so, swap filler caps with a friend. If the borrowed filler cap is silent buy a replacement for your car.