Denso (3324) SK16R11 Iridium Spark Plug, 1 Count (Pack of 1)

Great spark plugs, I just installed them on our 2005 Pontiac Vibe 2WD base model (same 1ZZ-FE engine as Toyota Matrix/Corolla), recently acquired with 148k miles. It looks like the plugs had never been changed, visual inspect revealed a good deal of wear (moreso on the ground electrode than the central electrode except for one), but honestly the car was running just fine. I changed the spark plugs along with some other things so that I have more of a baseline of knowledge about where the car's maintenance stands (very little records came with it).The plugs I pulled out were identical to the new ones, Denso SK16R11, apparently installed without any anti-seize (as they do at the factory). I went really slow when pulling the originals out, being careful not to strip the threads, due to some minor corrosion, giving each plug a slight turn until it stopped squeaking (which was indicative of some looseness, and stopped once the friction generated enough heat...), then let each cool back down while I did other things (transmission fluid change, work on one of the other plugs, etc.), and each one eventually came out just fine. Perhaps I could have taken the originals out more quickly, but was not willing to take the risk with the aluminum heads, and I figure if the originals had been in there for over 10 years and 148k miles, they deserved some respect and patience. They did squeak coming out but I've definitely seen worse in other cars.I installed the new ones without anti-seize and they went right in and torqued down to the proper manufacturer's spec like a breeze. Apparently the special plating on the threads that Denso and NGK talk about on these kinds of plugs that obviates the need for anti-seize works.Car is purring like a kitten, now. 4000 miles on the oil change (conventional oil) and the oil is still amber and still smells like new oil. I'm very impressed with this engine so far.If your car's owners manual calls for this plug or the NGK equivalent, you cannot go wrong with this plug. Meets manufacturer's design parameters exactly and a great price through Amazon.

I tested the resistance in all 4, they were within the range of .5 to 6 ohm — be careful not to damage the tip, you need to move it around to get the correct reading. The plugs are already gapped correctly to .43.I used dielectric grease on the white ceramic of each plug — not on the tip. The only issue is the amount of torque required. The QR code on the box pointed to Denso site, but the instruction is nowhere to be found.Based upon how tight the original spark plus were — they were really tight; I did half turn after finger tightening.As it turned out, the torque value should be 18 ft-lb. You should always double check the torque value from official source and not yourtube.If you don’t have a torque wrench, I would shoot for half turn, a little less is fine.It’s not rocket science.Use a magnetic socket or one that has the rubber insert that traps the spark plug in the socket, you don’t want to it to drop from the socket and damage the tip. Also, if the socket with the extension is not an one-piecer, tape the socket to the extension with duct tape, you don’t want to pull out the extension with the socket stuck to the spark plug inside the cylinder. Do the manual tightening very gently, don’t cross-thread it.The new plugs run fine, no misfiring, no trouble code. The engine feels smoother and more responsive.

These spark plugs are the OEM ones that Toyota uses. Made in Japan, and not china thankfully, so you can be sure you are getting the quality you want for your buck. While these are slightly more expensive, the iridium helps longevity of the plug. Mine were long overdue, so I pulled them out and changed them with my dad. They go in perfectly, and I had a check engine light (which was why I was thinking about changing them in the first place) and it seemed that with the change of these and the O2 sensors, my little car (2001 Prius) is back up and running, and still using all the OEM parts =] Very satisfied, will purchase again, especially with the exceptional quality of these babies. As a longtime Amazon customer, I rely on reviews from the Amazon community when making buying decisions. That being said, I only believe in giving honest and unbiased reviews. If this review was helpful to you in any way please click below.Thanks for reading!

I bought my 2006 Prius new. It now has 144000 miles on the odo. I have never tuned the car but noticed my mileage slipping and noticed a slight miss at idle. I decided it was time and ordered these plugs, mass air flow cleaner, PCV, and filters. I couldn’t find my feeler gauge so bought another. I cleaned the engine and hosed off the cleaner paying particular attention around the plugs so when removing no dirt falls into the cylinders. I looked up valve lash and checked that. A little off but close. The plugs needed gapping because they arrived out of their boxes and had been bashed around and into each other within the shipping box during shipment. I put a small dab of anti seize on the threads and torqued down the plugs. With the PCV valve installed, I replaced the filters, cleaned the mass air flow sensor and the throttle valve, and buttoned her up. One of the old pugs lost part of the insulator around the tip of the plug. No wonder I had a miss! Perfect OEM replacement plugs. Car runs better. I’ll have to replace the plugs more often then once every 14 years.