this problem has started about a week ago and i'm not too sure what i could be. When i'm accellerating from a dead stop as i hit about 40km/h (25miles) i hear this buzzing coming from somewhere underneath my car. Pretty sure its something from my exhaust not sure what part or what I could do to check which piece needs to be replaced or what it even may be and if i should replace it right away or wait.
The noise usually lasts for 3-4 seconds then stops then sometimes reoccurs when i further accellerate.

 

Look at your heat shield that runs along your exhaust system. Something might be bent, causing it to rattle a bit.

~Cheers~