Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

2004 Chevrolet Impala LSFACTORY OEM SERVICE PROCEDURE

Installation Procedure

Measure the spark plug gap on the spark plugs to be installed. Compare the measurement to the gap specifications. Refer to Ignition System Specifications . Correct as necessary.

NOTE: Refer to Fastener Notice in Cautions and Notices.

Install the spark plugs to the engine.
Tighten:
- If installing the spark plugs to a new cylinder tighten the plugs to 27N.m (20 lb ft).
- If installing the spark plugs to an existing cylinder tighten the plugs to 15N.m(11 lb ft).

Fig 1: Identifying Spark Plug & Wire

Courtesy of GENERAL MOTORS CORP.

Connect the spark plug wires to the spark plugs. Refer to Spark Plug Wire Replacement .

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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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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