truck is parked/off making odd noise

[MichaelMr2]

So I pulled into the garage today, turned off the engine and got out. I hear an odd noise coming from behind the rear drivers wheel.

"Buuurt buuuurt buuuurt" almost like the sound of a mobile phone on vibrate...

I could not locate the source. About 30 min later I went back out and it had stopped. WTH???

[acvdriver]

I have an 04 and it does the same thing. I think it's related to the fuel pump, although I could be wrong. I just recently was able to start parking in the garage, so I don't know how long it's been doing it. I think it's too low of a sound to hear outside with all the noise. I'll be interested to hear what this may be.....

[sequoiasoon]

Venting sound in area of left rear wheel well