Irregular Idle

Check in Order Listed:

^ Engine Control Module
Check MIL action (see How to Display and Read Diagnostic Trouble Codes). Is MIL coming on/are codes stored/is light on steady?

^ Idle Air Control Valve (IAC)
Perform Idle Air Control Valve tests as shown for Diagnostic Trouble Code (DTC) 14.

^ Other Idle Controls
Fast Idle Thermo Valve - Perform Fast Idle Thermo Valve test to verify air flow when cold.
Idle Adjusting Screw - Perform inspection/adjustment procedure for Idle Adjusting Screw.

^ Engine Coolant Temperature (ECT) Sensor
Perform Engine Coolant Temperature Sensor tests as shown for DTC 6.