GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Bonneville 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Cuts Out, Misses

Checks

Action

DEFINITION: Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases.

Preliminary
    • Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .
    • Refer to Visual/Physical Checks in Symptoms - Engine Controls .
    • Search for bulletins.

Fuel System
    • Check the fuel system pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injectors. Refer to Fuel Injector Solenoid Coil Test .
    • Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Check items which can cause an engine to run rich. Refer to Diagnostic Aids for DTC P0172 .
    • Check items that can cause an engine to run lean. Refer to Diagnostic Aids for DTC P0171 .
    • Check for fuel in the vacuum hose of the fuel pressure regulator. If fuel is present, replace the fuel pressure regulator. Refer to Fuel Pressure Regulator Replacement .

Sensor/System
    • Check for conditions which cause an incorrect idle speed.
       - Any throttle body tampering, excessive deposits, or damage
       - A restricted air intake duct or a dirty air cleaner element, refer to Air Cleaner Element Replacement .
       - Check for a large vacuum leak.
    • Check the throttle position (TP) sensor and the related wiring. Refer to DTC P0123 .
    • Check the EGR system:
       - Inspect the EGR pipes and the adapter for vacuum leaks.
       - Remove the EGR valve and check for a sticking pintle. Refer to Exhaust Gas Recirculation Valve Replacement .
    • Check the PCV valve for proper installation. Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical.
    • Verify the correct operation of the PNP switch by comparing the transaxle range switch input with the vehicle in drive and the gear selector in drive or overdrive.
    • Check for the following conditions:
       - Check for bent harmonic balancer interrupter rings.
       - Check for a damaged crankshaft position (CKP) sensor.

Ignition System
    • Check for the correct ignition voltage output using the following steps:
       - Clip the J 26792 Spark Tester to engine ground.
       - Connect one end of a spark plug wire to the spark tester. Leave the other end of the spark plug wire connected to the coil being tested.
       - Connect another spark plug wire between the remaining tower of the coil being tested and ground.
       - Crank the engine while observing the spark tester. A crisp blue spark should be observed.
       - Repeat the above steps for each coil.
    • If adequate spark is not present at the coils, check for the following conditions:
       - Inspect the coils for cracks, carbon tracking/arcing, or a resistance value outside the specified range.

Coil Secondary Resistance
5,000-8,000 ohms

   Important:: If carbon tracking is detected on any component, replace that component and the component's mate.

       - Inspect the spark plug wires for signs of arcing or cross firing, cracks, carbon tracking, plug boot damage, pinched wires, incorrect routing, or a resistance value more than the specified value.

Spark Plug Wire Resistance
3280-4921 ohms per meter (1,000-1,500 ohms per foot)

   Important: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent condition. Ignition components will arc to ground when a secondary component is malfunctioning.

       - Check for a malfunctioning ignition control module.
       - Check the ignition system wiring for a loose ignition module feed, ground connection, or damaged system wiring.
    • Remove the spark plugs.
    • Inspect the spark plugs for the following conditions:
       - Fouling
       - Cracks

   Important:: If carbon tracking is detected on any component, replace that component and the component's mate.

       - Check the spark plugs for signs of carbon tracking on the porcelain or arcing at the plug wire contact.
       - Check the spark plugs for incorrect gap. Refer to Maintenance Items in Maintenance and Lubrication.
       - Check the spark plugs for damaged electrodes.
       - Check the spark plugs for incorrect heat range. Refer to Maintenance Items in Maintenance and Lubrication.
    • If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
    • Check for the following intermittent ignition system conditions:
       - Check for an Intermittent CKP Sync or CKP 18X signal.
       - Check for an intermittent ignition feed circuit or sensor ground circuit to the crankshaft position sensor or the camshaft position sensor.
       - Check for a intermittent 3X reference signal.
       - Check for a intermittent camshaft position signal.

Engine Mechanical
    • Check engine mechanical for the following:
       - Check the compression. Refer to Engine Compression Test in Engine Mechanical.
       - Check for sticking or leaking valves. Refer to Cylinder Leakage Test in Engine Mechanical.
       - Check for worn camshaft lobes.
       - Check the valve timing.
       - Check for bent push rods.
       - Check for worn rocker arms.
       - Check for broken valve springs.
       - Check for excess oil in combustion chamber and leaking valve seals.
    • Inspect for incorrect engine parts, such as the following basic components:
       - The camshaft
       - The cylinder heads
       - The pistons, etc.
    • Refer to Symptoms - Engine Mechanical in Engine Mechanical

Additional Checks
    • Check the exhaust system for a restriction. Refer to Restricted Exhaust .
       - Inspect exhaust system for damaged or collapsed pipes.
       - Inspect the mufflers for heat distress or internal failure.
       - Check for a plugged 3-way catalytic converter. Refer to Restricted Exhaust .
    •  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 or decrease in RPM with little change in actual engine RPM indicates that EMI is present. Check the routing of the secondary ignition wires. Also, check the ignition coils for cracks, carbon tracking, or signs of arcing.
    • Check the intake and exhaust manifold passages for casting flash. Refer to Upper Intake Manifold Replacement and Lower Intake Manifold Replacement in Engine Mechanical.
    • Check for loose, worn, or broken motor mounts. Refer to Engine Mount Inspection in Engine Mechanical.