Loud Hum From Air Box

[lrwjr1964]

I had a loud high pitched whine or hum coming from under the hood. After doing a search seemed like it was my IAC. I cleaned my old IAC and the sound went away for a day and then came back. So I bit the bullet and got one from nappa auto parts. The high pitched sound is gone from the IAC area, but now I have this annoying hum coming from the airbox that was not there before. Does anyone else have this problem? If so how did you solve it. Once again I already replaced the IAC whith a brand new one. Can someone help?

 

[TPLYNCH]

You sure it's not one of the pullys, say your alternator for instance?

 

[Cali' Explorer]

Could also be one of the idler or tensioner pulleys, there should be one or two running directly unde the intake or intake tube. I've got a '97 V8, so I can't say for sure, but that's what I would check.