Weird squeek
 

I have a weird noise coming from the rear, kind or a rhythmic dry whistle. I am having a bit of a hard time describing it. Not present at low speed, and the sound or the pulsing stays the same at different speeds. It seems to start at highway speeds, I tried to take a video of it but it was not loud enough to hear.

I was wondering if it might be the fuel pump, although I guess it could be in the suspension.