How to Change Spark Plugs on a 2.4L Sunfire

The 1995 model year brought about some significant changes for two of General Motors' most popular entry-level vehicles -- the Chevy Cavalier and Pontiac Sunbird. The platform both vehicles were based upon was up for a complete overhaul. The Cavalier name remained attached to the redesigned Chevy vehicle, but Pontiac saw an opportunity for change, and swapped the Sunbird name for the Sunfire. From its release in 1995 through the 2001 model year, the Sunfire had an optional GT trim level that used a 150-horsepower, 2.4-liter, four-cylinder engine. Pontiac recommends replacing the spark plugs every 100,000 miles as a part of the Sunfire's basic maintenance schedule.

Check the gap between the center and ground electrode on the base of all four new AC Delco 41-942, or equivalent spark plugs, using a spark plug gap tool. The correct gap for the 2.4-liter engine is 0.048 to 0.052 inches. Exchange any incorrectly gapped plugs for new ones, as the recommended plugs are not adjustable.

Remove the four bolts securing the engine cover -- the plastic cover on top of the engine that reads "2.4L Twin Cam" -- using a ratchet and socket. Press the locking button on the wiring harness plugging into the driver's side of the engine cover, and pull the harness from the cover -- this harness actually connects to the coil pack assembly, which attaches to the underside of the cover.

Pull upward on the engine cover, using a slight wiggling motion to remove it -- notice the white assembly on the underside of the cover, this is the coil pack assembly. If any of the rubber boots from the base of the coil pack assembly remained stuck to a spark plug, pull the boot from the spark plug with a slight wiggling motion and press the boot back onto the bottom of the coil pack assembly.

Remove all four spark plugs, using a ratchet, spark plug socket and 6-inch extension. Hand-thread the four new spark plugs into the engine, and tighten them to 13 foot-pounds, using a torque wrench, 6-inch extension and a spark plug socket.

Apply a coat of dielectric grease to the inside of all four rubber boots on the coil pack assembly. Line the boots on the coil pack assembly up with the tops of all four spark plugs, and press the coil pack assembly onto the spark plugs until you feel it click into place. Tighten the four engine cover-retaining bolts to 16 foot-pounds, using a torque wrench and socket.