This is how I replaced the spark plugs on my Toyota Tacoma with the 4.0L 1GR-FE engine. The plugs are due to be replaced every 30,000 miles and you should use Denso or NGK plugs or you will have misfire issues down the road. Spark Plugs Anti-Sieze To start, You want to remove a couple things First, Useing a 10mm socket, Remove the engine cover Then, Using a 12mm socket, you need to remove the intake hose, and filter assembly There are 2 bolts on the hose, and 2 clips on the filter housing Then Remove the air filter cover and intake tube After the air intake and filter housing are out of the way, You can access the coils. First, Unplug and Remove the wire harness to them Then, Remove the 10mm bolt holding the coil on the valve cover. Only remove the bolt on the coil Then, Remove the coil In some cases, the coil gasket may stick to the valve cover. Make sure it comes up with the coil, and check to make sure it is seated properly on the coil After the coil is removed, remove the Spark Plug Using a little bit of Anti-Seize on the new Plug, Install the new Plug Thread the new plug in by hand. DO NOT cross thread the plug Reinstall the coil Plug the Harness back in until you hear it "snap" 2 more and the passenger side is finished The Driver side has a few more things in the way. For the most part, they can be pushed out of the way. First, you want to move this bracket (surge tank stay) by removing the top 12mm bolt, then loosening the bottom 12mm bolt. Then, Remove the vent hose Then, Remove the VSV connector, and the clip holding the wiring in the way Its tight, but take your time and remove the 10mm bolts holding down the coils and disconnect the electrical connectors. Now replace the plugs and reassemble in reverse order... Here is what the old plugs looked like... Thanks goes to chris4x4 for the write up.