something in my computer made a fart

Just now... something in my computer made a quick fart sound.  More like when a woman poots.  "Poot!".  I looked inside but all the fans seem to be whirring at normal speed.  What the fuck happened?

OP here

the sound happened again

I think a cord might be leaning into the fan, and at a certain point the fan hits it and smacks it away.

I replaced my video card fan a week ago.  Do fan problems typically tend to all come down on a nigga at once?  Never had this happen before on any of my previous computers