Rough Idle

Check in Order Listed:

- Engine Control Module
Check MIL action (see Diagnostic Trouble Code Extraction). Is MIL coming on/are codes stored/is light on steady?

- Idle Control System
Inspect all hoses and connections.

- Idle Air Control Valve (IAC)
Perform Idle Air Control Valve tests as shown for DTC 14.

- Emission Control System
Exhaust Gas Recirculation (EGR) Control system - If applicable to engine emissions system. - Perform tests to Exhaust Gas Recirculation Control System.
Positive Crankcase (PCV) Ventilation System - Perform test of Positive Crankcase Ventilation System.

- Fuel Supply System
Fuel Injector - Perform Fuel Injector test as shown for DTC 16.
Injector Resistor - Perform test of Injector Resistor.
Contaminated Fuel - Inspect for contaminated fuel.

- Manifold Absolute Pressure (MAP) Sensor
Perform Manifold Absolute Pressure Sensor tests as shown for DTC 3 & 5.