Weird buzz sound from under car....

[typeruz]

I bought my ITR about 3 months ago, and ever since the day i brought her home and parked her in the garage i've noticed a weird buzz sound.

i only hear it when parked and the car if OFF. it sounds almost like the ABS cycle you hear in most cars when it's started (like a little motor is warming up), but more high pitched. it lasts about 5 seconds, and returns every minute or so.
sometimes i hear it after slamming the car door shut. it's not always reproducable.
it sounds like it's coming from under the rear part of the car...almost in the area of the fuel pump (under rear seats). when in the garage, you can't miss it b/c of the echo on the walls, but otherwise it is rather faint. (it actually freaked my wife out once when she went to the garage at late night to get the laundry.)

originally i thought it was the metal cooling, but with listening to it over and over again, it's definetely not that.

is this normal??? what could it be?? i'm thinking it may actually be coming from the fuel pump, but i don't understand why a fuel pump would be doing that in the first place.

any help is appreciated.
thanks!!!

[Erik B]

wow got me on this one.....bump for a good question...

[ThisFlyGuy]

i think you should just lay under the car and listen for it next time- so atleast you know what area the sound is coming from.....engine area or rear section.....specifically....

[Dev]

If it sounds a bit like a fog horn or muffled trumpet it is a vapor release valve in the tank.

I have this same deal...what Ive been told is that your gas tank builds up pressure, obvious if you have opened the cap to put gas in it, and this valve releases the pressure when the car is off.

Depending on your geographic climate, altitude..etcetc, you will notice the sound more or in greater degree...and yes, it does come from the back of the car up near the fuel pump. I chased this thinking I was developing a vapor lock...I have 30k on the car now and still notice the noise from time to time. Nothing to burn out over

Hope this eases your mind
Dev

[Dave-ROR]

yep, the vapor purge is my guess as well. in some cars this valve makes a unique "Mooooo" sound like a cow.. at least ours is less annoying than that.

[type_r_556]

HAHAHAHAHAHA, i thought i was the only one with this noise, i noticed it too on my car, and i was like WHAT THE FUC#, but i thought my car was sad or something and wanted to be driven harder, hahahaha, j/k, no i thought it was the shocks in my rear hatch, and i was about to take it in for warranty, but was too lazy too, i know that sound cause it just randomly happens, and i'm like AHHHHHHHHH everytime, hahahah well problem solved, thanks guys.

[typeruz]

ahhhhh,
that fog horn and moooo description is it!!!

it's gotta be that valve.

thanks y'all. now i can rest a little easier knowing my baby is ok =).