2001 engine humming sound

I hear a weird humming sound when I press the gas pedal.it goes away when I press hard.also it sounds while shifting gears

Type of engine?
Maintenance history?

My best guess is that your mystery vehicle has a problem with a loose heat shield on the exhaust system, but if you give us more information, we may be able to be more specific.

Hmmm…Were the questions that I posed really difficult to answer?

Apparently (sadly) so