For 1990-2009 cars

Checks | Action
--- | ---
Definition: Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. This condition is not normally felt above 1500 RPM or 48 km/h (30 mph). The exhaust has a steady spitting sound at idle or low speed.
Preliminary |

• | Refer to Symptoms , Important Preliminary Checks Before Starting.

• | Search for bulletins.

• | Verify the PCM grounds for being clean, tight and in the proper locations. Refer to Ground Distribution Schematics in Wiring Systems.

• | Remove the air filter element and inspect for dirt or for being restricted. Refer to Air Cleaner Element Replacement . Replace as necessary.

Fuel System |

• | Perform the injector balance test. Refer to Fuel Injector Balance Test for procedure.

• | Test for a low fuel pressure condition. 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 .

• | Inspect items that cause an engine to run rich (long term fuel trim near -13%). For a rich condition, refer to DTC P0132 HO2S Circuit High Voltage Bank 1 Sensor 1 and DTC P0152 HO2S Circuit High Voltage Bank 2 Sensor 1 .

• | Inspect items that can cause an engine to run lean (long term fuel trim near 23%). For a Lean condition, refer to DTC P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1 and DTC P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1 .

Sensor/System | Use a scan tool in order to monitor the KS system for excessive spark retard activity.
Ignition System |

• | Wet down the secondary ignition system with water from a spray bottle. Wetting down the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as you apply water.

• | Test for proper ignition voltage output with spark tester J 26792 .

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

- | Correct heat range.

- | Wet plugs

- | Cracks

- | Wear

- | Improper gap

- | Burned electrodes

- | Heavy deposits

• | An improper spark plug gap will cause a driveability condition. Do the spark plug gapping using a wire gauge gap tool (J 41319). Determine the cause of the fouling before replacing the spark plugs if the spark plugs are gas or oil fouled. Refer to DTC P0172 Fuel Trim System Rich Bank 1 and DTC P0175 Fuel Trim System Rich Bank 2 for diagnosis of the rich condition or Oil Consumption Diagnosis in Engine Mechanical 5.7L for diagnosis of the oil fouling condition.

• | Visually/Physically inspect the Secondary ignition for the following:

- | Ignition wires arcing to ground

- | Ignition wires for proper routing

- | Ignition coils for cracks or carbon tracking

Engine Mechanical |

• | Inspect engine mechanical for the following:

- | Test compression. Refer to Engine Compression Test in Engine Mechanical 5.7L.

- | Sticking or leaking valves. Refer to Valve Train Diagnosis in Engine Mechanical 5.7L.

- | Worn camshaft lobes. Refer to Valve Train Diagnosis in Engine Mechanical 5.7L.

- | Valve timing. Refer to Valve Train Diagnosis in Engine Mechanical 5.7L.

- | Bent push rods. Refer to Valve Train Diagnosis in Engine Mechanical 5.7L.

- | Worn rocker arms. Refer to Valve Train Diagnosis in Engine Mechanical 5.7L.

- | Broken valve springs. Refer to Valve Train Diagnosis in Engine Mechanical 5.7L.

- | Excessive oil in combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical 5.7L.

• | For incorrect basic engine parts. Inspect the following:

- | Camshaft

- | Cylinder heads

- | Pistons, etc.

Additional Checks |

• | Inspect exhaust system for possible restrictions. Inspect for the following:

- | Inspect the exhaust system for damaged or collapsed pipes.

- | Inspect the exhaust manifold for a collapsed inner wall.

- | Inspect the mufflers for heat distress or possible internal failure.

- | Inspect for possible plugged Three-Way catalytic converters. Refer to Restricted Exhaust System Check .

• | Electromagnetic Interference (EMI) on the reference circuit can cause an engine miss condition A sudden increase in RPM with little change in actual engine RPM change indicates EMI is present. Inspect routing of secondary ignition wires, high voltage components (Near Ignition Control circuits) if a condition exists.

• | Inspect the intake manifold and the exhaust manifold passages for casting flash. Refer to Intake Manifold Clean and Inspect and Exhaust Manifold Cleaning and Inspection in Engine Mechanical 5.7L.