Buzz in front in

Now that is has gotten a little cooler here in Virginia, I have noticed a buzz/rattle (sort of like a bumble bee in a coke can sound) when I accelerate. It basically happens between 1000 - 1500 rpm's and sounds like it is coming from right under the motor - I have a 2007 tacoma -- any suggestions or need for worry? Thanks!

 

Climb under there and have someone rev the engine? 1000-1500 is really low RPM's. Loose something or other?

Vid/audio would be great.

 

Does it only buzz when you lightly push on the throttle, then stop when you let off?

 

Yes -

 

Alrighty then, my first and best guess since my truck did and is doing it again is it's the air box on the pass. inner fender, it happens where the air horn goes into the fender.
Easy to check, just remove the two bolts holding it to the inner fender & unscrew the clamp on the air tube, when you pull it off, you'll see the air horn that goes into the fender and a piece of cheap foam tape around it that collapses and lets the horn vibrate against the fender.
While it's off take the truck for a ride to see if the noise is gone.

 

I had a similar issue, it was the heat shield above the exhaust. The shied had broken around the outside of the nut so it wasn't holding anything any more so it was rattling around.