Tools You'll Need:
* Spark plug socket: A deep well socket that fits your spark plugs (likely 5/8" or 13mm). A flexible extension and universal joint are HIGHLY recommended to reach the rear plugs.
* Wrench: To loosen the coil pack mounting bolts. A ratchet with extensions will help.
* Ratchet: To turn the spark plug socket.
* Needle-nose pliers or a small pick: May be necessary to help remove the coil pack connector.
* New spark plugs: Use the correct type and heat range specified for your engine (check your owner's manual).
* Gloves: To keep your hands clean.
* Shop rag or clean cloth: To wipe away any dirt or oil.
* Torque wrench: (Highly recommended) to tighten the spark plugs to the proper specification.
Procedure:
1. Safety First: Disconnect the negative (-) terminal from your battery.
2. Locate the Coil Pack: The coil pack sits atop the rear three spark plugs. It's usually held down by a couple of bolts.
3. Remove the Coil Pack: Loosen and remove the bolts holding the coil pack in place. Carefully lift the coil pack away from the spark plugs. Be gentle as the connector is fragile. You may need needle-nose pliers to disconnect the electrical connector from the coil pack.
4. Remove the Spark Plugs: Using the spark plug socket, extension, and universal joint, carefully remove the three rear spark plugs one at a time. Be cautious not to drop the plugs into the engine. They can be difficult to retrieve.
5. Inspect the Spark Plugs: Examine the old spark plugs for signs of wear, fouling, or damage. This can help diagnose potential engine issues.
6. Install the New Spark Plugs: Install the new spark plugs by hand, screwing them in gently until they're snug. Then, use the spark plug socket and ratchet to tighten them to the manufacturer's specified torque. Do not overtighten. Using a torque wrench is crucial to prevent damage.
7. Reinstall the Coil Pack: Carefully reconnect the electrical connector to the coil pack and reinstall the coil pack onto the spark plugs. Secure it with the bolts you removed earlier, tightening them to the proper torque.
8. Reconnect the Battery: Reconnect the negative (-) battery terminal.
9. Start the Engine: Start the engine and listen for any unusual noises. Check for any leaks around the spark plug area.
Important Considerations:
* Access: The rear spark plugs on this engine are notoriously difficult to access. Be prepared for tight quarters and awkward angles. A mirror might help you see what you're doing.
* Torque: Using a torque wrench is essential to avoid stripping the spark plug threads or damaging the engine block. Consult your vehicle's repair manual for the correct torque specification.
* Gap: While unlikely to need adjusting on pre-gapped plugs, check your new plugs against your vehicle's specifications to be sure they're correct.
* Repair Manual: A repair manual specific to your 1998 Pontiac Grand Am 3.1L is your best resource. It will provide detailed diagrams, torque specifications, and other important information.
If you are uncomfortable performing this repair yourself, it's best to take your vehicle to a qualified mechanic. This procedure can be challenging for someone without experience.
