Cuts Out, Misses

Cuts Out, Misses Symptom

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 - Vehicle . Refer to Symptoms - Engine Controls .
Sensor Checks	Check the engine coolant temperature (ECT) sensor using a scan tool to compare the engine coolant temperature with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5°C (9°F) more or less than the ambient air temperature on a cold engine, check for a high resistance in the coolant sensor circuit or in the sensor. Refer to Temperature Versus Resistance . Inspect the mass air flow (MAF) sensor operation. Run the engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s refer to DTC P0101 .
Fuel System Checks	Check for a restricted fuel filter or an incorrect 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) , Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F) and Fuel Injector Balance Test with Special Tool . Check for water contamination of the fuel.
Ignition System Checks	Check for an ignition system misfire: IMPORTANT: Do not perform this test for more than 2 minutes in order to prevent damage to the catalytic converter. Start the engine. Remove one ignition coil at a time using insulated pliers. If there is an RPM drop on all cylinders (equal to within 50 RPM), refer to Rough, Unstable, or Incorrect Idle and Stalling . Check for spark on the suspected cylinders with a J 26792 Spark Tester or equivalent if there is no RPM drop on one or more cylinders. See Special Tools . If there is no spark, refer to Engine Cranks but Does Not Run . If there is spark, inspect the spark plugs for correct operation and good ignition system performance. Refer to Spark Plug Inspection . Check the ignition system for moisture, dust, cracks, burns, etc.
Engine Mechanical Checks	Check for any of the following engine mechanical problems: Faulty hydraulic lifter assemblies Broken or weak valve springs Incorrect valve timing Incorrect or worn camshaft Check the intake and exhaust manifold passages for casting flash. Refer to the Diagnostic Starting Point - Engine Mechanical .
Additional Checks	An engine miss condition can be caused by electromagnetic interference (EMI) on the reference circuit. EMI can usually be detected by monitoring the engine RPM with a scan tool. A sudden increase in RPM with little change in the actual engine RPM change indicates EMI is present. If a problem exists, check the routing of the secondary ignition wires and the high voltage components. Verify the powertrain control module (PCM) grounds are clean, tight, and in the proper locations. Refer to Engine Controls Schematics .