Mid-Throttle Buzz

[eblank8]

I have a 2001 Ford Explorer Sport SOHC (completely stock). The truck idles with no noise, just slightly lobey. I hear a strange buzz/hum on mid-throttle. If I just drive normally, I never hear the sound. But the instant that I want to gain some speed quick and push the gas over half way, I get the sound. It more more of a weird buzz/faint chatter/hum. Very hard to describe as I have never heard this sound before. I initially thought of an exhaust leak, but I cant seem to find any. I thought of the fuel pump, but the noise is in the engine bay. So I am thinking exhaust or vaccum leak. I was wondering if anyone else has encountered a similar problem before I start relacing random gaskets.

 

[Mbrooks420]

Welcome to the site. Does it sound like this ?
http://www.explorerforum.com/forums/showthread.php?t=191913&highlight=iac+dogfriend
If so it's fairly common, and easy to fix.

 

[eblank8]

Thank. I also looked into the IAC, and It also doesnt make a buzz at idle. The buzz is far fainter than that as well. I would call that a hum, my sound is more of a buzz.

 

[Mbrooks420]

A bearing in the alt, or a pulley idler?