GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 Engine 🢒 Engine Controls - 4.0L and 4.6L 🢒 Cuts Out, Misses

Checks

Action

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

Preliminary
    • Refer to Symptoms .
    • Search for bulletins.
    • Check PCM grounds for being clean, tight and in their proper locations.
    • Remove and check air filter element for dirt, or for being restricted. Replace as necessary.

Fuel System
    •  Perform injector balance test.
    •  Check for low fuel pressure. Refer to Fuel System Pressure Test .
    •  Check for restricted fuel filter.
    •  Check for contaminated fuel. Refer to Fuel Quality Diagnosis .
    • Check items which can cause an engine to run rich (long term fuel trim near -99%).
    • Check items that can cause an engine to run lean (long term fuel trim near 100%).

Sensor/System
    •  Using a scan tool, monitor KS system for excessive spark retard activity.
    • Check the EGR system for proper operation.

Ignition System
    • Wetting down the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as water is applied.
    • Check for proper ignition voltage output with spark tester J 26792. Refer to Secondary Ignition Diagnosis .
    • Remove spark plugs and check for the following:
       - Wet plugs
       -  Cracks
       -  Wear
       -  Improper gap
       -  Burned electrodes
       -  Heavy deposits
    • An improper spark plug gap will cause a driveability problem. The spark plug gapping should be done using a wire gauge gap tool (J 41319).
    •  If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
    •  Visually/Physically inspect Secondary ignition for the following:
       -  Ignition wires for cross firing.
       -  Ignition wires arcing to ground.
       -  Ignition wires for proper routing.
       -  Ignition Coils for cracks or carbon tracking.
    •  Wetting down the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as water is applied.
        Check for loose ignition control module ground.
    • Spark plugs for proper heat range. Refer to the owner's manual in order to determine the proper replacement of spark plugs.

Engine Mechanical
    • Check engine mechanical for the following:
       -  Check compression.
       -  Sticking or leaking valves.
       -  Worn camshaft lobe(s).
       -  Valve timing.
       -  Worn rocker arms.
       -  Broken valve springs.
       -  Excessive oil in combustion chamber-Leaking valve seals.
       - Low cylinder compression.
    •  For incorrect basic engine parts. Inspect the following:
       - Camshaft
       - Cylinder heads
       - Pistons, etc.

Additional Checks
    • Check exhaust system for possible restrictions. Check for the following:
       - Inspect exhaust system for damaged or collapsed pipes.
       -  Inspect mufflers for heat distress or possible internal failure.
       -  For possible plugged Three-Way catalytic converters by comparing exhaust system back pressure on each side of engine. Refer to Restricted Exhaust in Engine Exhaust.
    •  An engine miss condition can be caused by Electromagnetic Interference (EMI) on the reference circuit. EMI can usually be detected by monitoring engine RPM with a scan tool. A sudden increase in RPM with little change in actual engine RPM change, indicates EMI is present. If a problem exists, check routing of secondary ignition wires, high voltage components (Near Ignition Control circuits).