I have a 2001 Xterra that when I turn the engine off I can hear what sounds like a fan running near the back. I don't think it's a fan, but the full pump. It only runs for about 20-30 seconds after shut-off and doesn't sound abnormal. I called the dealership and all the recalls have been taken care of. Is it possible the fuel pump relay needs to be replaced? I'm not having any problems with it at the moment ie: starting it up or it dying on me. It primes just fine. Maybe i'm just paranoid because I just got it. Any thoughts on this would be appreciated.