When i start the 88 GTA and let it idle, there is no noticible noise but after i turn the car off (it hasn't moved at all) there is a humming/buzzing coming from the rearend of the vehicle which lasts about 10 seconds and then stops. any ideas?

 

probably a fuel pump but im not sure it should be one while the ignition is off...

 

Sounds like something blowing its nose? Does it for a couple of seconds, then waits 5 or 10 minutes and does it again for a half hour or more even, will do it more if the tank is low and the car has been driven a long time? ..... Never heard of it before.

But when my car was doing it, it was a certain little plastic relief valve, located in the rear end hump, just in front of the rear end, and just inside of the left wheel, on the end of a fuel line. AFAIK the dealer or possibly a place that carries the full AC/Delco product line is the only place to get it.

 

thats the fuel pump , and its normal . You should hear it also when you just turn the key to on , but don't crank it

 

I second that, it's the fuel pump. It stays on for a second or two after you turn the key off, I can always hear mine humming in the bowels of the tank before it goes to sleep...

 

ya the fuel pump was the only idea I had as far as the noise.
thanx

 

wow i wasnt aware of that. i thought that the pump only sounded when you turned the ignition on. thats why i wasnt sure.

 

mine has always seemed to make that noise when least expected. like hours after you shut it off, in the middle of the night, when fat girls walk by...

it almost sounds like a moo...