AH - Idle Vibration/Rough Idle

Description
This describes the operations necessary to diagnose an Idle Vibration/Rough Idle symptom. This will involve checking the Fuel, Air, Ignition, EGR, ECM, and other systems.
Refer to "Symptom Matrix Chart" for details.

Diagnostic Repair Procedure
Check the following:
1. Battery and Alternator
2. Main power supply and ground circuits
3. Fuel quality
4. Base Idle speed, ignition timing and throttle position sensor adjustment: BASIC INSPECTION AND ADJUSTMENT
5. Target idle speed: Spec = 625 ± 50 RPM (A/T)/700 ± 50 RPM (M/T)
6. IACV-AAC Valve operation: Use CONSULT-II, ENGINE -ACTIVE TEST -IACV-AAC/V OPENING
7. EGR: Confirm it is not stuck open
8. Ignition signal: P1320 - IGNITION SIGNAL
9. Fuel Pump and Fuel Pressure Regulator operation: Gauge should read 34 psi at idle and 43 psi when fuel pressure regulator vacuum hose is disconnected and plugged.
For inoperative Fuel Pump refer to FUEL PUMP CONTROL
10. Fuel Injectors: INJECTOR NON-DETECTABLE

Use CONSULT-II to check the operation of the following items:
11. P0100 - MASS AIR FLOW SENSOR
12. P0131 - FRONT HEATED OXYGEN SENSOR
13. P0125 - ENGINE COOLANT TEMPERATURE SENSOR
14. P0120 - THROTTLE POSITION SENSOR
15. P1706 - PARK/NEUTRAL POSITION SWITCH
16. Front Engine Mount control
17. Electrical Load signal
18. Power steering oil pressure switch

Other items to be checked as possible malfunction cause
19. PCV system
20. EVAP system
21. IACV-FICD
22. A/C circuit
23. Oil level and condition
24. Intake air leaks
25. Air Filter
26. Engine mechanical components
27. ECM