Disconnect the cable from the negative battery terminal, then remove the engine cover if equipped. For 2006 and later models, remove the upper intake manifold to access the rear bank ignition coils, while for 2005 and earlier models, disconnect the spark plug wire by pulling on the boot only, not the wire. Disconnect the electrical connector from the ignition coil and remove the mounting fastener(s); for 2005 and earlier models, each ignition coil is secured by two bolts, whereas for 2006 and later models, each ignition coil is secured by one bolt. Note that on 2005 and earlier 3.5L V6 engines, only three ignition coils are used, mounted over cylinders 2, 4, and 6, with spark plug wires feeding to the other cylinders. The ignition coil on cylinder 2 connects to cylinder 5, cylinder 4 connects to cylinder 1, and cylinder 6 connects to cylinder 3. Pull the coil straight up and out of the valve cover after removing the bolt(s), ensuring the boot is in good condition for 2006 and later models. Installation is the reverse of removal, and dielectric grease should be applied to the spark plug boot or coil boot prior to installation.