Buzzing noise when accelerating
This is my first post on this forum. I have a 2013 C300 Sport 4matic. I've been having this issue for a while but I'm not sure if it really is a problem.
When I'm at cruising speed around 70mph (~2000rpm) when I hit the gas pedal, there is a noticeable buzzing noise, which I'm not sure it is from the engine or the exhaust. When I let the gas pedal go the noise disappears. If I manually switch the gear to 5th (~3000rpm) the buzzing also goes away.
I'm planning to go to the dealership next week to check it out. Any suggestions or it is normal?
BTW I had my ECU tuned by Kleeman

Thanks in advance!


