2005 DC 8Cyl Spark Plug discrepancy

Hi everyone, I’m looking to change the spark plugs and it looks like the previous owner installed some NGK Iridium IFR6A11’s and the part that the stealership gave me is 90919-01166. There is a discrepancy in the offset as the iridium has much more (I don’t have the equipment to tell exactly) space than the OEM plugs I was given.

From what I’ve read most people who use the 90919-01166 plugs are 00-04 V8’s but upon looking up several different OEM parts dealerships they say that it also fits 05-06 V8. Anyone experience this before?

 

Using either NGK or Denso as shown in an 05 owners manual is preferred. The Iridium you mentioned is one of the proper choices but not from ebay, amacon and the likes. Way too many knockoffs

 

important to note though, there's a typo in the Owner's manual. This should be "SK" not "KS"

 

When you say there is a discrepancy in the offset, do you mean the electrode gap?

 

Yes, sorry that’s what I was trying to get at. I know that the gap widens over time but it caught me off guard.

I’ve since installed the ones I bought from the dealer and noticed that my engine was dying/stalling out when I slowed to a stop or got to a stoplight. I’ve since taken out and cleaned the throttle body and MAF sensor. I’m going to test it later today. The truck was running perfectly at higher RPM’s but it was idling low.

 

Interesting. With authentic Iridium plugs, instructions tell you clearly not to gap them, they're pre-gapped properly. I always check mine, but have yet to find a discrepancy. They all have cardboard rolls fitted over the electrode that makes it virtually impossible to close the gap in transit, from crushing or otherwise.

That said, if the gap is smaller in the dealer-supplied plugs, visibly smaller, that's probably a problem with the dealer plugs not being iridium or pre-gapped, and undergapping would cause the issues you're seeing.

Buy what's shown in the owners manual, but note the discrepancy I pointed out in the model#. We've already seen one person with a V6 on here get the wrong plugs from a dealer. This is why it's best just to avoid the dealer on that specific part, and go with what's in the manual instead.

 

That makes sense. I think I saw that the plugs I got are in the manual, but I’m on standby to see if I need to get different plugs. Everything I’ve read in previous threads describe the current issue due to ECU reset from battery being disconnected and a disgusting throttle body and MAF.

Fingers crossed, we’ll see!

 

If battery is disconnected for 5-10 minutes, it's normal for the ECU to begin a relearn cycle after. It's generally a good idea any time you're dealing with air/fuel sensors or spark generation to pull the neg battery cable for a period of time to get there.

But if the gap was visibly different to the human eye, like very-very different, I'd have some concerns. I presume the dealership gave you plugs that were iridium (I didn't look up the p/n to check) and you at least verified the gap, or if they were non-iridium, you gapped to spec, right?

 

Our Tundras idle in the 700 RPM range once warmed up.

 

I looked at the old spark plugs and only two had what I would call abnormally large gaps. The rest were within range by eye judgment. I unfortunately don’t have the tool to check the gaps.

The spark plug that I installed are

$4 Denso K20R-U Denso 3122 Spark Plug

Denso K20R-U. I called three different dealers and they all confirmed that those are the correct plugs for my truck.

 

Those are platinum tip plugs.

While it's true, those are the fit in the part system if you want the lower performance plugs. The owners manual says to use iridium tip plugs, which are the higher end. But I digress, your truck, use what you want. Either is technically correct.

However, with those plugs, you need to make sure the electrode is gapped per the owners manual Bubba posted above, i.e. 1.1mm

The tool at the local auto parts store to gap things is like $3.

A lot of pre-assembled generic toolkits in the plastic case you get everywhere actually come with a gap kit. But I recommend just getting one of the round-shaped keyring ones they have at the store if you'll only ever use it for spark plugs, rather than buying a feeler gauge.

 

Thank you everyone for the input! I’ve got great news and she’s running like a charm after cleaning the MAF and throttle body.

It typically idles at 700 but on occasion (after a sudden stop) drops to 550 rpm for 15-20 seconds before returning to normal. It no longer dies/stalls out at stoplights.

I may one day go back and do Iridium plugs but I can’t seem to find concrete evidence for one over the other except for different brands?

Thanks again everyone!!

 

Having difficult time finding that in my 04 or even the 05/06 ?

Agree

As for our older Tundras, it's my understanding our ignition coils are designed for High Voltage/High Resistance, which at the end of the day for EPA's sake, helps with NOX(cylinder temps).

Copper(U-Groove)

• Higher Voltage/Higher Resistance
• Lower NOX(cylinder Temps)
• Change every 30K miles according to Toyota Maintenance schedule

Iridium

• Lower Voltage/Lower Voltage
• Higher NOX(cylinder temps) by a long shot
• Last up to 100K
• Higher cost compared to Copper but last longer

Original U-Groove | DENSO Auto Parts

Shop Genuine OEM Spark Plugs for Your Toyota

IMHO, U-Groove vs Iridium is not necessarily high end vs low end but simply either is technically correct.

At the end of the day, the most important point would be to change plugs according to mfg recom.

 

You posted the page from the '05 manual above showing SK-20-R11 as the recommended part. It's an iridium plug.
OP installed OEM p/n 9091901166 which translates to K-20-RU. It's a platinum plug.

(I'm hyphenating those on purpose to keep the forum from auto-linking to scAmazon)

I see what you're saying and totally agree. What I'm saying about quality is, in general, iridium tech is higher-end, more efficient than platinum tech. Iridium lasts longer, it's stronger and harder, and has better wear longevity. It's a higher quality plug, better technology as long as you buy from legitimate vendors and stick with OEM-suggested brand/model.

 

To that I agree.

Where I erred was focusing on high/low end comment as it relates to U-Groove vs Iridium in an 05 VVT-i thread.
Discussion on 2UZ non-VVT-i(best gen)vs VVT-i(less gen) 00-06 1st Gens, U-Groove vs Iridium would be better served in a dedicated thread.

 

Actually, the

$4 Denso K20RU Denso 3122 Spark Plug

Denso K20RU and Toyota 9091901166 are standard copper core w/ nickel electrode spark plugs. No platinum, no iridium. They are the factory plugs for 2000-04 models with 30k intervals.

 

Ackchyually , 9091901166 is the

$4 Denso K20R-U Denso 3122 Spark Plug

Denso K20R-U. But OP has an '05, and should be using iridium plugs per the manual.

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Toyota's own parts system has a blurb about platinum tipped plugs on this part, maybe they're wrong? It's where I got the platinum info from. My reading comprehension sucks sometimes though, you may be right.

​

 

I know, that's why I grouped the two together. But you can buy the

$4 K20RU Denso 3122 Spark Plug

K20RU in Denso packaging, rather than the nice red Toyota boxes. I've got a set of the Toyota boxed plugs from the local Toyota dealer ready to go in an 03 V8. They are clearly not platinum plugs.

The Toyota line is generic, probably same on all of their spark plug listings.