Loud Hum From Engine.

[Iceman83]

Sometimes when I start my Explorer, I hear a loud hum. And when I give it some gas, it goes away, but returnes when I let off the gas. It goes away completely after I drive it somewhere. It doesn't do it all the time.

 

[my98nnj]

It's in the stickys.

http://www.explorerforum.com/forums/showthread.php?t=191915

 

[gtyates]

yep, need to replace the IAC. Not expensive, and very easy repair. Just did my '96 for the same reason.