For 1990-2009 cars

Inspections | Action
--- | ---
DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down without a change in the accelerator pedal position.
Preliminary |

• | Refer to Important Preliminary Inspections before starting in Symptoms - Engine Controls .

• | Search for bulletins.

• | Inspect the engine control system grounds for being clean, tight, and in the correct locations. Refer to Engine Controls Schematics . Ensure the resistance between the engine control module (ECM) housing and the battery negative cable is less than 0.5 ohms.

• | Verify that the ECM and ECM bracket fasteners are at the correct torque.

• | Ensure that the driver understands the operation of the transmission torque converter clutch (TCC) and A/C compressor operation as explained in the owner's manual. Inform the customer how the TCC and the A/C clutch operates.

Fuel System |

• | Test for incorrect fuel pressure. Refer to Fuel System Diagnosis .

• | Test for a restricted fuel filter. Refer to Fuel System Diagnosis .

• | Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• | Verify that each injector harness is connected to the correct injector/cylinder according to the firing order.

• | Test the fuel injectors. Refer to Fuel Injector Solenoid Coil Test .

• | Test the items that cause an engine to run rich. For a rich condition, refer to DTC P2178 or P2180 and DTC P2188 or P2190

• | Test the items that can cause an engine to run lean. For a lean condition, refer to DTC P2177 or P2179 and DTC P2187 or P2189 .

Ignition System |

• | Inspect for the correct installation of the ignition coil seals. Incorrect installation may allow water to enter the spark plug area. Inspect for moisture and corrosion.

• | Test for proper ignition voltage output with a J 26792 Spark Tester. If you suspect an ignition system condition exists, refer to Electronic Ignition (EI) System Diagnosis .

• | Remove the spark plugs and inspect for the following conditions:

- | Correct heat range

- | Wet plugs

- | Cracks

- | Wear

- | Improper gap

- | Burned electrodes

- | Heavy deposits

- | Refer to the following procedures:

• | Spark Plug Replacement

• | Ignition System Specifications

• | Spark Plug Inspection

• | If the spark plugs are gas, coolant or oil fouled, determine the cause before replacing the spark plugs. Refer to the following procedures:

- | Test the items that cause an engine to run rich. For a rich condition, refer to DTC P2178 or P2180 and DTC P2188 or P2190 .

- | For diagnosis of coolant contaminated spark plugs, refer to Loss of Coolant .

- | For diagnosis of oil fouled spark plugs, refer to Oil Consumption Diagnosis .

• | Inspect the crankshaft position (CKP) sensor for the correct resistance. The sensor resistance may be out of range after a hot soak. Measure that the resistance remains within 700-1,200 ohms at all temperatures.

• | Inspect the spark plug boots and terminals for burning or micro-arcing, corrosion, and damage to the insulation.

Additional |

• | Inspect the vacuum hoses for splits and kinks. Verify that the connections and routing are as shown on the Vehicle Emission Control Information Label, refer to Emission Hose Routing Diagram .

• | Inspect for a condition with the camshaft actuator system. A camshaft actuator that is stuck in the full advance or retard position may cause this symptom. Refer to DTC P0011, P0014, P0021, or P0024 .

• | Test the TCC operation. A TCC applying too soon can cause the engine to spark knock, surge or chuggle. Refer to Torque Converter Diagnosis .

• | Test the A/C clutch for the correct operation. Refer to Symptoms - HVAC Systems - Automatic .