Idle speed fluctuates (MIL works OK, no DTCs set)
Diagnostic procedure
1.
Do the PCM idle learn procedure.
2.
Check the idle speed.
3.
Do the carbon accumulation check.
4.
Inspect the PCV valve.
5.
Troubleshoot the A/C signal circuit.
6.
Check the A/C refrigerant amount.
NOTE: Turning the A/C to ON under the conditions that the A/C refrigerant amount is out of specification (excessive or too little) may cause the idle speed fluctuation.
Also check for
Incorrect valve adjustment
Intake air leaks