The spark plugs in a Pontiac Grand Prix are built to last up to 100,00 miles. Old or damaged spark plugs drastically reduce the life of Grand Prix engines. Changing spark plugs on a Grand Prix takes about 30 minutes to complete and helps improve the vehicle's gas mileage.
Park the Grand Prix and allow the engine to cool. The time it takes to cool the engine depends on climate, temperature and how long it was last driven.
Locate the spark plug wires, which are halfway down the sides of the Grand Prix engine.
Grab the spark plug wire by the boot and twist it to release the lock. Pull back to remove the wire from the spark plug. Replace one spark plug at a time. Spark plug wires that are crossed or put into the wrong place cause major cylinder and engine damage.
Unscrew and remove the old spark plug with the socket and wrench.
Lubricate the threads of the new spark plug and the wire's boot with anti-seize compound.
Screw in the new spark plug by hand and test its tension. The tension on Grand Prix spark plugs needs to be between 11 and 15 ft-lbs. Adjust the spark plug accordingly.
Replace the spark plug wire. Turn it 1/2 turn in both directions until you hear it click in place.
Repeat Steps 2 through 7 for the remaining spark plugs.
