Code P0320?

Hello,

The trouble code:
P0320 : No crank reference signal at PCM

This code gets triggered when there is no signal from the crankshaft position sensor present during startup.
When there is an issue with the crank sensor the you could have hard time starting the engine. Also it can stall the engine regardless of whether its idling or driving.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

The high idle issue sounds like the idle air control valve issue. The IAC is located on the throttle body.
The IAC gets dirty overtime as air particles gets stuck to the valve. It can have idling issue when it gets enough buildup.
Sometimes you can clean out the IAC and it can fix the idling issue.

Here are few helpful article:

https://www.2carpros.com/articles/how-a-idle-air-control-valve-works
https://www.2carpros.com/articles/idle-air-control-valve-service
https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

I have attached diagrams for your reference.

Please let me know of any questions.

Thank you.