Procedure
- Remove the battery on the driver side and the washer bottle on the passenger side. Those two moves buy you the clearance that makes this job civilized.
- Pull the intake duct and, on tight cars, unbolt the A/C lines' bracket - never open the A/C system itself, just move the hardline slightly.
- Disconnect each coil pack connector, remove the coil hold-down bolt, and work the coil out with a gentle twist.
- Crack each plug loose with a thin-wall magnetic socket on wobble extensions. Feel the angle before applying force - cross-threading an aluminum head here is an engine-out repair.
- Read the old plugs as you remove them: even light-tan centers are healthy; one plug oily or peppered with specks means compression-test that cylinder before you button up.
- Gap-check the new plugs even if pre-gapped, thread them in by hand until seated, then torque to spec - usually around 13-15 ft-lb, no more.
- A dab of dielectric grease in each coil boot, coils back on, connectors clicked, and reassemble. Start it before reinstalling the battery tray trim so you can hear any misfire immediately.
Work at your own risk. Torque values and procedures vary by vehicle — always confirm against the factory service manual for your exact model.