About 6 months ago my car started to make a crazy noise when it was just setting there turned off. I could not have driven it for 48 hrs and it still makes the noise. it sounds like a sick cat or a ghost moaning!!! Sometimes its every 2-5 min, and other times once every 20 min or not at all, I cant even really tell where its coming from, but it seems to be somewhere around the rear driver side wheel 1/4 panel area, but it could be from anywhere. It did not start untill we started making road trips from LA to PHX to look for homes. This was the 1st time that I really put alot of miles on my car. I have not noticed any other problems at all.
The only mod i have done to my '02 4cyl 4dr accord was to install a CAI about 1yr ago.

 

Mine used to do the same thing. I don't notice it anymore. I thought it was the fuel pump turning on, but I never figured it out.

 

is it under warranty? I have no clue what it could be without actually hearing it. I guess you could try pulling codes, but i doubt you'd get one, its worth a shot though. I dont know what to tell you.

If its under warranty, take it to the stealership and tell them whats up.