Surges and/or Chuggles

Definition: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal.

1. Was the "On-Board Diagnostic (OBD) System Check" performed?

[YES] Go to Step 2.
[NO] Go to OBD System Check. Initial Inspection

2. a. Perform a bulletin search.
b. If a bulletin that addresses the symptom is found, correct the condition as instructed in the bulletin.
c. Was a bulletin found that addresses the symptom?

[YES] Verify repair.
[NO] Go to Step 3.

3. Was a visual/physical check performed?

[YES] Go to Step 4.
[NO] Go to Visual/Physical Check. Visual/Physical Check

4. a. Be sure that the driver understands A/C compressor operation as explained in the owner's manual. Inform the customer how the A/C clutch operates.
b. Is the customer experiencing a normal condition?

[YES] System OK.
[NO] Go to Step 5.

5. a. Check the fuel control Heated Oxygen Sensor (HO2S) 1. When monitored on the scan tool, the H02S1 should respond quickly to different throttle positions. If it doesn't check for silicon or other contaminants from fuel or use of improper RTV sealant. The sensors may have a white powdery coating. Silicon contamination sends a rich exhaust signal which causes the Powertrain Control Module (PCM) to command an excessively lean air/fuel mixture.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 6.

6. a. Check the fuel pressure. Refer to Fuel System Pressure Test.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 7.

7. Monitor "Long Term Fuel Trim" on the scan tool. Is "Long Term Fuel Trim" in the negative range (rich condition)?

[YES] Go to Step 8.
[NO] Go to Step 9.

8. a. Check items that can cause the engine to run rich. Refer to Diagnostic Aids in DTC P0172.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 10.

9. a. Check items that can cause the engine to run lean. Refer to Diagnostic Aids in DTC PO171.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 10.

10. a. Check for proper ignition voltage output with the spark tester J 26792.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 11.

11. a. Check for a loose ignition control module ground.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 12.

12. a. Remove the distributor cap and check for cracks or carbon tracking.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 13.

13. a. Visually/Physically inspect the secondary ignition wires. Check for the following conditions.
- Verify that all ignition wire resistance are less than the specified value.
- Verify that ignition wires are correctly routed to eliminated cross-firing.
- Verify that ignition wires are not arcing to ground. Spraying the secondary ignition wires with a light mist of water may help to locate an intermittent problem.
b. Was a problem found?

[VALUES] 22.4 ohms.

[YES] Verify repair.
[NO] Go to Step 14.

14. a. Check ignition coil secondary resistance.
b. Replace the coil if it is not within the specified range of resistance.
c. Did the coil require replacement?

[VALUES] 9 k-ohms - 12 k-ohms.

[YES] Verify repair.
[NO] Go to Step 15.

15. a. Remove the spark plugs and check for gas or oil fouling, cracks, wear, improper gap, burned electrodes, heavy deposits or improper heat range.
b. If spark plugs are fouled, the cause of fouling must be determined before replacing the spark plugs.
c. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 16.

16. a. Check the injector connectors.
b. If any of the connectors are connected at an improper cylinder, correct as necessary.
c. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 17.

17. a. Check the PCM grounds to verify that they are clean and tight. Refer to the PCM wiring diagrams.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 18.

18. a. Visually/physically check the vacuum hoses for splits, kinks and proper connections and routing as shown on the "Vehicle Emission Control Information" label.
b. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 19.

19. a. Check the exhaust system for a possible restriction:
- Damaged or collapsed pipes.
- Internal muffler failure.
b. Measure backpressure and determine if the catalytic converter is plugged.
c. Was a problem found?

[YES] Verify repair.
[NO] Go to Step 20.

20. a. Review all diagnostic procedures within this table.
b. If all procedures have been completed and no malfunctions have been found, review/inspect the following:
- Visual/physical inspection.
- Scan tool data.
- Freeze Frame data/Failure Records buffer.
- All electrical connections within a suspected circuit and/or system.
c. Was a problem found?

[YES] Verify repair.
[NO] Contact Technical Assistance.