So i'm having all kinds of weird issues with my Cruz that I believe may be inter related to a possible electrical issue, maybe alternator?

I have attached a video with a noise that the car is making. It seems to happen after the car has run for a few minutes and I've also noted that when driving if I accelerate the noise will go away until i back off the accelerator and it comes back.

A couple other things have started happening right around the same time:

1. When the car is put in park the motor will rev up to about 3k-3.5k RPMS and then slowly back off.
2. Randomly the temp gauge will shoot up to the point that I get a message that the AC has been shut off because of engine heat OR it will shoot all the way up and I'll get a stop engine message. I know the car is not overheating as there are no other signs of it overheating AND the temp gauge will generally come back to normal and everything will be fine.

Things i've done since this all started and the issues still persist.

I did have a code for the Mass Airflow Sensor (seems to be a default code for everything these days)
tried cleaning then changed Sensor
changed valve cover gasket
changed plugs
changed serpentine belt

Thanks in advance for any help, this is driving me crazy,