what is this noise?

So i'm in my garage smoking and this noise starts.. sounds kinda like a tire pump you plug into the cig lighter only alot quieter coming from around the rear axle of my 07 access cab prerunner sr5 that has been parked and off for 7 hours.

Anyone know what it is?

 

Gas tank letting some pressure out! its a something like that

 

P.24 of my 2010 manual states that about 5 hrs after the engine is turned off you may hear sound coming from under the vehicle for several minutes. This is the sound of a fuel evaporation leakage check and, it does not indicate a malfunction.

 

Thanks, it freaked me out a little.

 

Heard this tonight while in my garage and was like WTF.......

Came in and onto TW. Found the answer in about 2min....... Search IS your friend!

Thanks TW!!!

 

x2
Exactly what i was about to say!