AC - Hesitation/Surging/Flat Spot

Description
This describes the operations necessary to diagnose a Hesitation/Surging/Flat Spot 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 or sticking open or operating when conditions call for no EGR. P1402 EGR SYSTEM
8. 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
9. Fuel Injectors: INJECTOR NON-DETECTABLE
10. Ignition signal: P1320 - IGNITION SIGNAL
11. Knock Sensor circuit: P0325 - KNOCK SENSOR

Use CONSULT-II to check the operation of the following items:
12. P0100 - MASS AIR FLOW SENSOR
13. P0131 - FRONT HEATED OXYGEN SENSOR
14. P0125 - ENGINE COOLANT TEMPERATURE SENSOR
15. P0120 - THROTTLE POSITION SENSOR
16. P0500 - VEHICLE SPEED SENSOR
17. P1706 - PARK/NEUTRAL POSITION SWITCH

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