Humming noise from front left Options

[boomer3]

Hey guys, just picked up a 94 gt4, i'm loving it! I've noticed a bit of a humming noise from the left front end of the car. The noise is not related to rpms, or whether the car is moving or not. I can hear it while i'm driving, but it comes on and off periodically if i'm idling. Also, when idling if I open up the hood it appears to be coming from somewhere near the airbox, and sounds as if its some type of auxiliary pump or something. When it goes off, I can rev it up a little, and it usually comes back on. Let me know if this is making any sense at all. Thanks for the input!

[boomer3]

Hmmm, interesting. I have the GT4, so it would seem that it could be this w2a pump. However, it sounds very similar to what lilgreen is describing with his gt, so it might be something that is common between both of them. I was wondering if it was associated with the A/C but i'm not convinced. It really does sound like a pump of some sort to me. I can't find a search function on this forum, but what is the w2a pump?? Is is an auxiliary pump for the intercooler?

To add to what lilgreen said, the sound almost always stops when you come to a full stop and idle for a little bit, ie over 10 - 20 seconds, and I can get it to come back if i rev her up a bit at idle.