help please

[Jasonisgood]

so occasionally when i go over a bump in the road or when im decelerating i can hear something spin up under the hood, it dosent cause any acceleration and dosent happen every time so i cant confidently take it to my mechanic to have him look at it. i have no idea what it could be and was hoping to get some help as this is my wife's daily driver and don't want it to die on her.
help please

 

[PopRichie77]

Wow, that's a hard one without actually hearing it.
Check the power steering fluid level, check the motor mounts, check for a loose alternator make sure the belts are good. check everything associated with the belts.
Turn the heater fan off and see if the noise goes away.