2001 Maxima SE with High Idle Speed Problem

[2001I30MAX]

When I start the engine, (or when the engine is 'cold'), after a minute or two, it registers a norman idle speed (hovering over 700 to 800rpm) but after about 30 minutes of driving (when engine is 'hot'), say, while I am waiting for traffic light, I notice high idle speed (1000 to 1200rpm) in "Drive" and I have to press the brake harder than normal to hold the car. When I put in "Park", the rpm jumps to anywhere from 1800 to 2300 and stays there. It's been like this for about a month now.

Has anyone experienced what I am going through and can you share with me any diagnosis/solution you might have for this situation? I am wondering if this is a sign of a part going bad.
FYI, it has 121k miles and past 3 to 6 months, all 6 ignition coils and 4 O2 sensors were replaced.
I appreciate your input in advance.

[loystock]

Do you have CEL (verify it comes ON with ignition ON and normally goes off with engine running)? Get a free scan from Autozone and the likes for any trouble code.

You may have trouble code P0505. If you're lucky, it may be just a matter of cleaning the Throttle Body and IACV (Idle Air Control Valve) and then doing IALV (Idle Air Volume Learning, prerequisites are Gas Pedal Released Learning and TB Closed Position Learning). But it could also be due to faulty IACV. The IACV has a stepper motor with the driver (power amplifier) inside the ECM. In some cases, a shorted IACV stepper motor can also 'fry' the ECM. So hopefully, it's not the ECM as it can get expensive to replace and requires re-programming (otherwise, engine will not start due to NATS - Nissan Anti-Theft System)

The above-mentioned items have been covered numerous times before so doing a SEARCH should yield lots of useful info. Let us know the result of your preliminary diagnostic.