Some things you should try first. Unplug 02 sensor and make some test run. If it is real lean condition, it will stumble really bad. If it is a false lean condition, it will run much better.

You need to address that high idle speed as top priority. Things to check

IAC valve
Thermostat
Coolant sensor
Vacuum leak at intake. Plug all vacuum lines to be sure and see how the idle goes. You will need to revert to stock setting the throttle body for the test