2004 Chevrolet Impala LSFACTORY OEM SERVICE PROCEDURE

Removal Procedure

  1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical - 3.8L.
  2. Remove the spark plug wires (2, 4, 6) from the spark plugs at the rear of the engine using the following steps:
    1. Note the position of the spark plug wires before removing the wires.
    2. Twist the spark plug boot 1/2 turn before removing the boot.
    3. Gently pry the heat shield up from spark plugs using the J 38491  . See Special Tools and Equipment .
    4. Remove the spark plug wire from the spark plugs at rear of the engine.
    Fig 1: Spark Plug Wires (Even)
    GM194244Courtesy of GENERAL MOTORS CORP.
  3. Remove the spark plug wires (1, 3, 5) from the spark plugs at the front of the engine using the following steps:
    1. Note the position of the spark plug wires before removing the wires.
    2. Twist the spark plug boot 1/2 turn before removing the boot.
    3. Gently pry the heat shield up from spark plugs using the J 38491  . See Special Tools and Equipment .
    4. Remove the spark plug wires form the spark plugs at the front of the engine.
    Fig 2: Spark Plug Wires (Odd)
    GM194231Courtesy of GENERAL MOTORS CORP.
  4. Remove the spark plug wires from the ignition coils.
    5. Fig 3: Removing Spark Plug Wires From Ignition Coils
    GM194220Courtesy of GENERAL MOTORS CORP.
  5. Remove the spark plug wire retaining clips from the rear, front and top of the engine.
  6. Remove the spark plug wires from the engine.
  7. When replacing the spark plug wires transfer any of the following:
    • Boot heat shields
    • Spark plug wire conduit
    • Spark plug wire retaining clips
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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