To service the spark plugs, routing the cables first properly prevents ignition noise, cross ignition, and short circuits. First, remove the air cleaner lid, disconnect the inlet air sensor and the makeup air hose, and disconnect the negative battery cable. Subsequent to that, disconnect the cable from the ignition coil after removing the upper intake manifold, making sure to grasp the top of the spark plug insulator, and rotate the boot 90°.Remove the spark plug cable by pulling it straight up. Use a quality socket with rubber/foam insert to take out the spark plug and check its condition. While installing the new spark plug, start it by hand to prevent cross threading. Tighten the spark plug with a torque of 17.5 Nm. Tapered seat plugs must only be tightened to a torque of 2 N.m (13±2 ft. lbs.) or less. Once installed, place the spark plug insulator over the upper end of the spark plug tube, reattach the spark plug cable to the coil, reinstall the upper intake manifold, reconnect the negative battery cable, and install the air cleaner lid along with the inlet air temperature sensor and makeup hose.