Wooooo noise

I test drove a 2005 Tacoma today with the V6 auto. The truck runs and drives good but there was a pretty loud wooo noise at around 5mph and below and when stopped. It might have made the noise at higher speeds too but the tires/road noise covered it up. I even put it in neutral to see if the noise went away thinking it was transmission or torque converter related but the noise was still there. Any ideas what that could be?

 

Turbos spooling?

 

Didn't think about that,that's gotta be it!

 

Does that bitch have whistle tips?!

 

No whistle tips. The noise seemed to be coming from the front.

 

Throttle body spacer? Aftermarket intake?

 

That's what I thought when I was driving it but it was stock under the hood.

 

I just thought about this,the truck had HID headlights. Would the ballasts make a noise like that?

 

You would hear the ballast at idle though.