GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Skylark 🢒 Engine 🢒 Engine Controls - 3.1L 🢒 Cuts Out, Misses

Checks

Action

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

Preliminary
    •  Refer to Intermittent Conditions .
    •  Search for bulletins.

Fuel System
    • Check system fuel pressure. Refer to Fuel System Pressure Test .
    •  Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis Testing.
    •  Check items which can cause an engine to run rich (long term fuel trim significantly in the negative range). Refer to Diagnostic Aids for DTC P0172.
    •  Check items that can cause an engine to run lean (long term fuel trim significantly in the positive range). Refer to Diagnostic Aids for DTC P0171.
    •  Check for fuel in the Fuel Pressure Regulator vacuum hose.

Sensor/System
  1. Check for conditions which cause an incorrect idle speed.
    2. • Throttle body tampering, excessive deposits, or damage. Refer to Fuel Metering System Component Description .
    • Restricted air intake system. Refer to Air Intake System Description .
    •  Large vacuum leak.
  2. Check the TP Sensor and related circuit wiring. Refer to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage .
  3. Check the EGR system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .
  4. Check the PCV Valve for proper operation. Refer to Crankcase Ventilation System Description .
  5. Check the Transaxle Range Switch input with the vehicle in drive and the gear selector in drive or overdrive. Refer to DTC P0705 Transmission Range Switch Circuit .
  6. Check the following for damage:
    7. •  Bent harmonic balancer interrupter rings.
    •  Damaged Crankshaft Position Sensor.

Ignition System
    • Check for proper 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 to the coil being tested.
       -  Connect one end of another spark plug wire to the other coil tower; connect the other end of the spark plug wire to 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 coil(s), check for the following conditions:
       -  Coil(s) - Cracks, carbon tracking/arcing, or a resistance value outside the specified range.

Coil Resistance
5000 - 7000 ohms (5K - 7K ohms)

       -  Spark Plug wires - Signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range.

Spark Plug Wire Resistance
7000 ohms (7K ohms).

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

       -  Defective module.
       -  Ignition System Wiring - Loose ignition module feed or ground connection, or damaged system wiring.
    •  Remove spark plugs and check for the following:
       -  Fouled plugs
       -  Cracks
       -  Wear
       -  Improper gap
       -  Burned or damaged electrodes
       -  Improper heat range or reach
    •  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:
       -  Intermittent CKP 24X Signal.
       -  Intermittent ignition feed circuit or sensor ground circuit to the crankshaft position sensor or the camshaft position sensor.
       -  Intermittent 3X reference signal.
       -  Intermittent camshaft position signal

Engine Mechanical
    • Check engine mechanical for the following:
       -  Check compression.
       -  Sticking or leaking valves.
       -  Worn camshaft lobe(s).
       -  Valve timing.
       -  Bent push rods.
       -  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 converter. Refer to Restricted Exhaust System Check and Exhaust System.
    •  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).
    • Check for intake and exhaust manifold passages for casting flash.
    •  Check for faulty motor mounts.