Today I changed the spark plugs on my Gen 1 Toyota Tundra with the 2UZ-FE 4.7L V8 engine. The truck has more than 161,000 miles and as far as I can tell the plugs were last changed at 90,000 miles. I used Genuine Toyota Parts as always. This model year Tundra used an extended life U groove copper plug, not iridium. I used what Toyota calls for. They are part 90919-01166 and are marked K20R-U. The old plugs were in use for more than 71,000 miles. The plugs only cost me $1.66 apiece at the local Toyota dealer where I get a good discount, for a grand total of $13.28 worth of parts to last me another 70,000 miles.
The engine has a coil-on-plug design, with each cylinder having its own spark plug and ignition coil. The truck was driven in the morning with the old plugs and allowed to cool then while still warm to the touch, then the bolts on the ignition coils were sprayed with Kroil and let it soak in for an hour before starting the job.
Here's what the passenger side looks like before I cleaned off the coils and numbered them with a white paint Sharpie. From radiator to firewall the coils are numbered 2,4,6,8 and the driver's side is 1,3,5,7.
After cleaning and numbering the coils, remove the electrical connectors by pinching the tab and pulling straight up. Then I cleaned all the pins of the connectors with DeOxit D5 contact cleaner.
The #3 has some hoses obstructing it and #7 has some metal pipelines. Remove the retaining bolts using a ratchet wrench and 10mm socket, and put them in the magnetic parts tray then pull the coils out and set them aside. I sprayed the bolts with Dupont silicone lubricant with Teflon. I noticed two of the coils had oil on the outside of them. I cleaned them all off thorougly, then after removing the plugs and by wrapping a shop towel around a wooden coffee stirrer, soaked up any excess oil inside the cylinder hole area. After cleaning the coils including the rubber grommets, I also sprayed DeOxit D5 contact cleaner on the electrical connector as well as the spark plug contact inside the coil's tube. After letting them soak and shaking out the excess cleaner I set them aside while I changed the plugs.
I removed the old spark plugs using a magnetic spark plug socket on a 10" wobble extension. I got it from Amazon it is called LEXIVON 5/8" swivel magnetic spark plug socket, 3/8" drive, Made in Taiwan. It's a great tool that cost under $12. For the #7 plug near driver's side firewall, there was steel tubing over the plug and I had to use the ratchet wrench just to loosen the plug, then had to remove the wrench and just hold onto the socket extension itself to spin the plug out. It was tight but doable. The other seven were a breeze.
The new plugs I painted the threads with Permatex Anti-Seize then replaced them with the new plugs. They are torqued to 12 ft-pounds but I did it by hand just don't hand tighten and give it a bit of an extra twist. The old U-groove copper plugs were well worn after more than 71,000 miles but the Tundra was still running fine.
After getting all the plugs in, I reinstalled the coils in their numbered order and tightened all the bolts then put the electrical connectors back on. They click into place. Truck started instantly and went for a 20 mile drive. I runs great. My most recent tank of gas was 15.5 MPG so let's see if the new plugs make a difference.