For 1990-2009 cars

Checks | Action
--- | ---
DEFINITION: A steady pulsation or jerking that follows engine speed, usually more pronounced as the engine load increases. The exhaust has a steady spitting sound at idle, low speed or on hard acceleration.
Preliminary Checks |

• | Refer to Diagnostic System Check - Engine Controls .

• | Refer to Symptoms - Engine Controls .

Ignition System Checks |

• | Check the spark plugs for correct operation and performance. Refer to Spark Plug Inspection .

• | Check for the proper secondary voltage output with a J 26792 Spark Tester, or an equivalent. Refer to Electronic Ignition (EI) System Diagnosis .

• | Check for the correct ignition timing. Refer to Ignition System Timing Adjustment .

• | Run the engine and spray the ignition system with water in order to check for secondary voltage shorts.

• | Check the engine reference signal of the camshaft position (CMP) sensor with a scan tool. Observe the Engine Speed parameter while operating the engine at the speed of the concern. The scan tool should indicate steady and linear RPM readings while running. If the erratic values, such as sudden spikes or drops in engine speed are displayed, the engine reference signal is not stable enough for the engine to run properly. Inspect the CMP sensor signal rotor and housing for worn bushings or drive coupling. Inspect for electromagnetic interference (EMI) of the reference signal.

Engine Mechanical Checks |

• | Check for any of the following engine mechanical problems:

- | An incorrect valve lash

- | Any broken or weak valve springs

- | An incorrect valve timing

- | An incorrect or worn camshaft

• | Refer to Engine Compression Test in Engine Mechanical 2.0L.

• | Check the intake and exhaust manifold passages for casting flash.

Fuel System Checks |

• | Check for a restriction in the fuel supply system. Check for the correct fuel pressure. Refer to Fuel System Diagnosis .

• | 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 with Special Tool .

• | Check for water contamination of the fuel.

Additional Checks |

• | Verify that the PCM grounds are clean, tight, and in the proper locations. Refer to Engine Controls Schematics .

• | Check the Service Bulletins for any updates or information.