For 1990-2009 cars

#### Surges and/or Chuggles Symptom

Checks | Action
--- | ---
DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if it speeds up and slows down with no change in the accelerator pedal.
Preliminary Checks |

• | Refer to Powertrain On Board Diagnostic (OBD) System Check .

• | Refer to Symptoms .

• | Be sure the driver understands the A/C compressor operation.

• | Use a scan tool to make sure the reading of VSS matches vehicle speedometer. This excludes vehicles with electronic transmissions where some variation between VSS and the speedometer is normal.

Sensor Check | Check the Heated Oxygen Sensor (HO2S) Sensor 1 and Sensor 2 performance. Refer to DTC P0130 through DTC P0141 Diagnostic Aids.
Fuel System Checks |

• | Check if a Rich or Lean system can cause the condition. Drive the vehicle at the speed of the complaint. Monitoring the Fuel Trim may help identify the problem.

- | Lean -- The Long Term Fuel Trim will be greater than 20%. Refer to Diagnostic Aids.

- | Rich -- The Long Term Fuel Trim will be less than -20%. Refer to Diagnostic Aids.

• | Check the fuel injectors. Perform the Fuel Injector Coil Test Procedure and the Fuel Injector Balance Test Procedure. Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) and Fuel Injector Balance Test .

• | Check the fuel pressure while the condition exists. Refer to Fuel System Diagnosis .

Ignition System Checks |

• | Check for the proper secondary voltage output with a spark tester (J 26792 or equivalent).

• | Check the spark plugs for any of the following conditions:

- | Wet (fuel fouled) plugs.

- | A terminal screw that is bent or loose (rotate and pull).

- | A ceramic insulator that has cracks, carbon tracking or deposits (red or black dust)

- | A tip insulator that has cracks, carbon tracking, deposits (oil, carbon, glazing, fuel additive), or is loose (rattles).

- | A center electrode that is loose (wiggles side to side)

- | An incorrect spark plug gap that is too large or too small.

- | Platinum pads that are missing.

Additional Checks |

• | Check the PCM grounds for being clean, tight, and in their proper locations. Refer to PCM Wiring Diagrams.

• | Check the generator output voltage.

• | Check the vacuum lines and hoses for kinks or leaks. Refer to the Vehicle Emission Control Information label.