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The one thing that worries me is that reading this tutorial I found myself confused, since I have no idea what the parts referring to are.
pics are in the first two posts. Ask specifics if you want confirmation as to the referred parts or you can google for the specific lexus parts so you can see them individually. After removing the cover, you really just need to identify the coilpacks.
If you're wondering what a coilpack is -- in the old days there'd be one coil for the entire engine, and there would be a distributor to send the high voltage it produced to the individual sparkplugs. This was a high-maintenance setup, as you'd have to change out the distributor cap and the rotor (the part that spun in time with the engine) every couple of years. If dirt or grime got inside, or if the plastic cracked, you'd get a misfire. Every now and again, you'd have to adjust the position of the distributor so the high voltage would arrive at each cylinder at the correct time, which required special tools.
Old-style coil
Old-style distributor
About 20 years ago cars starting changing from one single coil to a coil per cylinder. This let the engine computer control the timing on a per-cylinder basis which produced way more power and better emissions (it can even fire multiple times per stroke, ensuring complete ignition of the gas vapors). They look like this (this photo isn't from a GX, but gives you the idea)
Coilpack
The new coilpacks can potentially last the life of the car, and are maintenance free. The downside is they cost more to replace when they go bad, and you have to unbolt them and remove them before changing plugs.
Thank you All for the great DIY info for Spark Plugs Change. I am not a handy guy at but @Chip kind a encouraged me to do it myself in an other thread so Thanks Chip.
I was quoted anywhere between $299 to $499 for the spark plugs replacement. Finally i ordered via Ebay SK20R11 8 pc for $56 and free shipping.
I didn't do it completely by myself and had help from my brother in law as he worried that i would strip those threads. But i learned a lot and did 1 on drivers side and all 4 on passenger side.
It took roughly around 4 hours because we ran in to issues on number 3 on the drivers side and started getting resistance and the plug wouldn't go in smoothly.
On both sides the middle two just came out freely as if they were not even torqued.
But it all worked out well and i followed all the cautions and steps mention allover this thread. The idle is very smooth now. I did disconnect the battery before 1st start as well.
I changed them at 121K to me they look pretty worn.
Also we did not gap new plugs but new ones looked they had more gap in between then the old ones.
Just did my 04 GX today. Actually the original plugs do not look too bad for 12 yrs 120k miles. The first four on bank 1 were a bit tight to loosen. With engine warmed up, the four on bank 2 were a lot easier to loosen.
No gap adjustment for Iridium plug per a label note on the engine.
So since you have just changed the plugs, how is the engine response to the accelerator.? I see my gas mileage improved a little and idle is quieter but acceleration is more the same. I was expecting a little more responsive throttle after the new plugs but this is my first V8..
I have also changed spark plugs on my 11 Accord yesterday and it has an improved throttle response and its a v4 so not sure.
I think it runs a little smoother now. It is wife's car. Can't tell too much difference.
Just happen to note that you had DENSO as original. My 04 had NGK IFR6A11 as original. I checked online that the DENSO SK20R11 is the replacement part which is what I got.
I noticed the same thing with your picture with NGKs as original. Not sure may be the supplier got changed in 08.
Here is one interesting fact, when i did my spark plugs on 07 4runner V6, 3 plugs on the right or left side were NGKs and 3 on the other side were Denso's. I confirmed that on T4R forum and was really confused
I also noticed one of the original plugs was not tightened down and had a lot of dry brownish coloring on the rubber coil tube compared to the others.
Yep, same thing on mine. Number 3 (from front) on the driver's side. The plug was only screwed in a couple of turns. All of them were way too loose, but that one in particular was almost out and it had scorched up the coilpack pretty badly.
The good news is that it was the source of my ticking sound, which I had assumed was caused by an exhaust manifold leak.
04-06-16, 05:58 PM
I did disconnect the battery before 1st start as well.
