This has been going on for quite a while now whenever I'm driving and I hit 45mph I hear this noise that sonds alot like I metal vibrating under my hood. I cannot tell the exact location but ut sounds like its on the passenger side only and it doesn't do it at any other speed except at 45mph. I can drive a mile an hourslower and you dont hear a thing and I can drive a mile an hourfaster and not hear a thing. A suggestions as to what it may be?

 

It it continuous or just a brief noise?

 

Check all the boots around your wheels and steering components. I hada torn boot and mine had a similar problem. And if it's a wheel boot, it can lead to serious wheel bearing damage.