Just found them for $14.24 each. I will pick them up and install them tonight.

 

Same plug on Rockauto is $12.99 so with shipping you're probably ahead buying local.

 

Yup, plus I won't have to wait for them to arrive either. After what you guys told me, I want to get this done ASAP.

EDIT: Oh and it gets better, I over estimated the mileage; I went through my eBay history and turns out I installed these July 2021. With my driving habits that means these plugs only have about 13-15k miles on them.

 

Ok guys I swapped the plugs out last night, but I'll be honest, it's VERY hard to distinguish the difference between the OEM units and the ebay "knockoffs." I had 2 extra "knockoff" plugs laying around (package of 8 was the best deal I found at the time) so I compared them and took some pics, take a look.

The packaging was identical, and the only real differences I noticed was the blue lettering on the plugs (OEM have a bolder and darker font) and the knockoffs have a "+" sign at the top, take a look.

In all of the photos below, the dealer OEM plug is on the left, whereas the "knockoff" is on the right.





Are we sure those are knockoffs and not subtle production changes? After swapping the plugs, the car seems to feel a little smoother (might be placebo though) and there's no CEL yet but scanning DID reveal a pending P0430 code like before, ugh.

 

Google Denso spark plug fakes. Denso has a write-up highlighting the knock-offs vs real McCoys. There is a difference in lettering and stamping. This forum has discussed this many times and Chinese knock-offs have been an issue on Ebay for many years. I got fooled once by Ebay fakes, but never again. OEM Toyota plugs don't lose their Iridium tips after 10-15k miles. Fakes don't last.

I'm assuming you cleared all codes before installing the new spark plugs. A CEL will only be thrown after two cycles seeing the same issue. Not good if you already have one pending.

I'd also recommend some good premium gas and injector cleaner in case you carboned up your injectors with incomplete combustion from the fake plugs.

 

Yeah I see that now, wow. I'm glad that you guys helped me catch this.

I didn't clear the CEL with a scan tool however I had the battery unplugged while I was swapping the spark plugs; figured that should have the same effect. I cleared the pending code after I found it yesterday with my scan tool and have driven about 30 miles since then, no CEL yet. I also ran Cataclean through the car yesterday.

I'm already expecting to replace the bank 2 cat, however if the CEL manages to stay off for the time being then that will be a bonus for sure.

 

Welp after about 40-50 miles the infamous CEL is back. Oh well. Time to start shopping around for a cat. (maybe I'll just run a defouler for the time being, we'll see).

At least this experience helped me realize I was running knockoff plugs in the car and you all helped me catch that before one broke apart inside and wreaked further havoc.

Truthfully though I don't think the fake plugs damaged the cats; they must've already been on their way out. Never had any misfires and the car had reasonable fuel mileage (19-23 mpg depending on conditions) and performance. Truthfully I haven't noticed a significant difference after swapping to the genuine Denso units either; I guess it's more of a long term thing.

 

Sorry to hear about your CEL returning. I'd still recommend replacing the front O2 sensor prior to getting a new CAT.

Your call, your $.

 

Yeah, I may try to switch the sides first (new Denso upstream sensor is nearly $130 on Rockauto and I've already thrown a few hundred bucks at this stupid cat issue).

Oddly enough though, Rockauto lists the same part number for Bosch upstream sensors, whereas Denso has 2 different part numbers for each bank. A quick glance in the engine bay shows that both pigtails appear to be the same length. I wonder why Denso shows 2 different parts?

 

You could always get an O2 extension to get you by if you don't want to spend the money now on the exhaust. It takes the O2 sensor out of the main stream of exhaust and will clear your code. The Cat is still bad but if the CEL bothers you that is an option. The extensions are cheap and can be found online.

 

Way ahead of you lol. I installed a brass 90 degree elbow last week and the CEL is gone. My state doesn't inspect vehicles either so as long as the CEL is off, it should pass emissions. Been about 300 miles since the install and CEL has not returned.

I had a hard time wrapping my head around a $700 repair that doesn't affect performance whatsoever.

 

I'm in the same state and have had mine on for at least 2 years. No issues with emissions testing. Mine is also the driver side. I actually went far enough to take the exhaust manifold off to inspect and it was fine. Was not fun to take off as there is literally no room.

 

Oh haha I didn't notice you were from CT as well. I didn't bother taking mine apart but I'd imagine it's the same as yours. If it eventually clogs then sure I'll replace it, but for now, fughettaboutit.

 

CT does not check for emission readiness?

 

if my cats ever go bad on my gs460 I’ll just remove them completely and run 02 extenders. Glad they worked for you and you’re “good to go” now.