2002 Nissan Altima P0507. Idle control system RPM higher than expected

First you should clean out your throttle body. next is your vehicle surging or just plain idling high? if its surging you should check the IAC and EGR valves. You may have a vacuum leak this guide should help.

https://www.2carpros.com/articles/engine-idles-too-high

Please go over this guide and report back.

IAC is idle air control it sets the idle for the engine, it is located on the side of the throttle body.

The EGR is exhaust gas recirucaltion, it takes the unburned exhaust gases and reburns them just like the PCV valve, it is located next to the throttle body also.

Cleaning the throttle is the last thing you should do on this car. This is what typically leads to this code.

The idle parameters need to be reset or the throttle body needs replaced. Can only be done by someone with proper software/scan equipment to program it.