Charcoal canister buzzing sound

[4wd4runner]

I have a 3.4L 4Runner and after I shut off the engine the charcoal canister makes a buzzing sound. Anyone know what it is or why it does it

 

[habanero]

96's like to moo...there's a fix, all you need to do is make a little air space, it's pretty simple. I used a mustard tin I had laying around....
Post 1097
habanero's 1996 4Runner Build-Up Thread - Page 55 - YotaTech Forums

and some info on it...
https://sites.google.com/site/bugeyebug/4runner-evapbuzz
The part the article refers to is no longer available, but really, it's just an air space.