GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Firefly (Canada) 🢒 Engine 🢒 Engine Controls - 1.0L 🢒 Cuts Out, Misses

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 Symptoms .

Ignition System Checks

Check for an ignition system misfire:

  1. Start the engine.
  2. Remove one spark plug wire at a time with insulated pliers.
  3. An equal RPM drop on all cylinders (within 50 RPM) indicates a common condition. Refer to Rough, Unstable, or Incorrect Idle and Stalling .
  4. No RPM drop on one or more cylinders indicates a cylinder specific condition. Check for spark on the suspected cylinders with a J 26792 spark tester or equivalent.
  5. If there is no spark, Refer to Engine Cranks but Does Not Run .
  6. If there is spark, check the spark plugs for any of the following conditions:
    7.  - Wet (fuel fouled) plugs.
     - A terminal screw that is bent or loose (rotate and pull).
     - A ceramic insulator that has cracks, carbon tracking or deposits (red or black dust).
     - A tip insulator that has cracks, carbon tracking, deposits (oil, carbon, glazing, fuel additive), or is loose (rattles).
     - A center electrode that is loose (wiggles side to side).
     - An incorrect spark plug gap that is too large or too small.
     - Platinum pads that are missing.
    • Check that the spark plug wire resistance does not exceed 30,000 ohms.
    • Check the distributor cap and the distributor rotor.
    • Check the ignition system for moisture, dust, cracks, burns, etc.
    • Run the engine and spray the secondary ignition system with water in order to check for secondary voltage shorts.

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 Engine Compression Test in Engine Mechanical.

Fuel System Checks
    • Check for a restricted fuel filter.
    • Check for the correct fuel pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injector solenoid for sticking, erratic operation.
    • Check for water contamination of the fuel.

Additional Checks
    • Check the PCM grounds for being clean, tight, and in their proper locations. Refer to Ground Distribution Schematics in Wiring Systems.
    • Check the Service Bulletins for any updates or information.