How to Replace an '01 Toyota Tacoma's Spark Plugs

The 2001 Toyota Tacoma has a coil-on-plug ignition system and uses Autolite XP iridium XP3924 spark plugs. The iridium is a very high temperature, burn-resistant coating on the electrode of a spark plug. Many plugs feature iridium coats; however, the Autolite is the original equipment material replacement. Iridium plugs resist fouling and gap expansion due to heat from arcing better than other standard plugs. This results in a longer time interval between replacements.

Instructions

1

Make sure the engine is cold before removing the spark plugs. The Tacoma engine has aluminum heads, and the spark plug case is made of steel, thus the spark plugs will expand faster than the aluminum in the head. This makes the spark plug threads extremely tight when warm, causing the threads in the head to strip if the plug removal is attempted when the head is warm.

2

Remove the top engine concealment cover by lifting it up -- this will dislodge the plastic prongs from the rubber grommets. Disconnect the electrical connectors on the coils by depressing the tab on the connector and pulling it off.

3

Remove the 10 mm bolt securing the coil to the valve cover. Lift up and twist the coil from side to side to dislodge the spark plug boot from the porcelain on the plug. Lift the coil and attached spark plug boot out of the spark plug access hole in the valve cover. Remove the spark plug, using the extension and spark plug socket. Turn the spark plug counterclockwise to remove it.

4

Gap the new spark plug to .44 mm, using the gapping tool. Insert the spark plug into the spark plug socket and insert the socket into the spark plug hole. Thread the plug in as far as possible, by hand, to prevent cross-threading. Tighten the plug snugly. Over-tightening will stretch the threads to the point where the spark plug can no longer be removed, thus damaging the cylinder head.

5

Insert the coil over the plug and push down to snap the spark plug boot on the plug. Install and tighten the 10 mm bolt. Plug in the electrical connector. Use the same process for all plugs.

6

Replace the engine concealment cover by aligning the prongs with the holes in the rubber grommets and pushing it down.