Rough Idle

Check spark plugs, spark advance, ignition system wires and connections, starter solenoid for internal shorting (except 2.5L), and trigger wheel pin. See BASIC TESTING article. See SYSTEM/COMP TESTS article regarding the following procedures.

• Check MAP sensor circuit and vacuum hose.
• Check injector harness connectors.
• Check coolant temperature sensor for shorted sensor or circuit.
• Check for proper idle control system operation.
• Check for shorted, open or misadjusted TPS.
• Check EGR valve operation.
• Check for shorts or opens in oxygen sensor circuit.
• Check PCV valve operation.