Do you always have this noise we you start the engine? Have you don any change of oil last time?
the humming noise is coming from a bad ground on you stereo
where is the humming noise coming from? if it's coming thru the speakers and matches the rev tone of the engine, then you have a bad ground in your stereo.
radiator fan.
is the humming coming from the front end of the vehicle? i have a 1996 explorer with the same issue. yes the noise come from the front but not all the time seems to make the humming noise when it gets hot
Most likely the humming noise is coming from a contactor located in the outdoor unit if you hear the noise outside or from the air handler or furnance located inside the home,if the hum is inside the home
its probably your radiator
Not much info there but my guess would be the the fuel pump.
Depending on where the sound is coming from, it may be your fuel pump. Sometimes they are noisy.
Certain types of tires may cause a brief humming noise after your initial acceleration. The transmission may also cause a brief humming noise.
Check the bearings.
Check the wheel bearing.
Perhaps the cooling fan is running?