Kizashi Club

Sounds like an electric fuel pump is stuck but starts after engine has been off for some time. "Dealer" no help.

Sounds like the same issue as posted by fjroman2 (Weird sound - thoughts?!?!?). Here's the explanation;

LEAK DETECTION PUMP
NOTE:
Your vehicle has a pump to regularly check the vehicle’s evaporative emission control
system for leaks. This check is performed approximately five hours after the engine is
turned off. During this leak check, you may hear a sound coming from the vehicle for
several minutes. This sound is normal and does not indicate a malfunction.

You beat me to it lol, was going to post the link~~

Pretty funny that 2 of us had the same concern within 2 days of each other. It is a little disconcerting when you go out to your car 5 hours after you last drove it and it is making sounds...lol!!