This is a guide on how to replace the ignition coils in your 3.4L V6 Toyota 4 runner. This is also works for the 3.4L V6 Toyota T100, 3.4L V6 Tacoma, and 3.4L V6 Tundra.

Tools needed:

• 10mm socket
• Screwdriver
• Basic pliers (to remove wire harness clips)
• Extension at least 3 inches. This can be done without one, but it makes this a lot easier. 
• 5/8 inch spark plug socket

The 3.4L 4 Runner only has 3 ignition coils for all 6 cylinders. You will notice that each ignition coil has a spark plug wires attached to it. This is called a waste spark setup. Each coil shares the spark with the spark plug wire.

1- Remove the air intake/box with the 10mm socket. You can also use a screwdriver to remove the clamps if your 4 Runner still has the original ones.

2- Remove 2 vaccum hoses that are attached to the airbox, and gently wiggle the air box up and remove it. We stress to be gentle as these are aging beyond 10 years and it can be easy to tear the rubber during removal. 

3- The 3 ignition coils are now exposed. Unclip the connector, and the spark plug wire from the coil and use the 10mm socket to remove each ignition coil.

4- Simply install each ignition coil, and you are finished!

If you wish to change the spark plugs during this process, you can do so as well as they are exposed. For the driver's side cylinder bank, the diagnostic box needs to be removed. It is only clipped on, not bolted on. You can unclip thediagnostic box, to gain access to spark plugs. Some vacuum hoses may appear to be blocking them, but they are not. You can simply move the hoses temporarily to gain access to the spark plugs.