My spark plug story...

So I bought my 1st gen at 164k miles 4 weeks ago and knew I was going to tackle the regular maintenance one by one starting with the spark plugs.

Well, a week after I put in these plugs (below), my gas mileage went way down, lost a ton of power, and truck began to stall when idling in park.



So I went to Toyota yesterday and asked for OEM plugs from the parts department. Slapped these babies in (below) last night and man what a difference in mpg and performance overall.


Anyway, I may not have installed the Iridium's properly, but I also read somewhere after the fact that iridium are actually not recommended for the 3.4. But feels good having a much smoother ride now. Thought I'd share

 

Welcome to Tacoma World. We like pics! Especially 1st Gen pics.

 

Welcome! Want to see pics of your truck, I love the way the 1st gen looks.

Love it when I clean the MAF sensor or replace old spark plugs and the truck runs way better after that.

 

There's a sticker on there from factory saying only use dual electrode. It probably fell off, pretty sure it's because of the shared coils.

 

is that the reason why?
doing some DIY investigations here on a REAL crappy running taco and the other type of plugs were put in last year, the ASE guy said the single work better last longer
had numerous major other stuff(s) done as well over the past year that might also contribute to the latest findings or not... i really Do Not Know

 

She's so pretty.. I feel very fortunate. and the color is just perfect imo. I bought a kit off of eBay from another thread that came complete with belts, water pump and timing belt. Plan on doing that in the next month or so. In the mean time my rear diff is leaking and I'm pretty sure it's the gasket, I just don't want to pay $1k to fix it.

 

The ASE guy got it backwards. The twin ground should last longer. The plugs are fired twice per cycle, not just on the ignition/power stroke. Besides that, owners have found better drivabilty and MPG using the Toyota recommended plugs.

 

the ASE guy was Not a Toyota shop guy, if it matters at all LoL which it really does not... all these jokers are pretty much cut from the same cloth
all i recall after change in style is it Did tweak/change the engine operation just a bit
mostly with engine shut off cycle down
and the MPG did not noticeably change for the few months after
they were pricey plugs, too... i think 25$ each at their markup from AAP

twin ground Only last 30k per the rec's i have seen for the 5VZFE or is it 60? i need to doublecheck on that

BUT! this truck has been having Other performance issues for a longass spell that so far are undiagnosable
maybe it is related somehow someway to those plugs

 

30k sounds about right, 60k is way too long. Being fired twice per cycle makes for a shorter plug life, but, it's believed that the dual ground last longer in that application.

 

Dont use the Denso TT's in a truck or large suv....

they are most likely engineered for small direct inject turbo jobs....
they needed a plug that wears out as fast as the engines.


Any modern iridium or platinum one spec'd for the truck should do

if you were an old engine....you'd need a big spark too.....

 

Doing this as well, the FSM specifies

$18 Denso K16TR11 Spark Plugs, Pack of 4

Denso K16TR11 and O'Reilly carries them. Side note, these were seven bucks + change, wife's Rav4 uses Denso SK16HR11, and they're almost thirteen bucks apiece. Both are Iridium tipped, so it was around $48 for four in the Rav4 and $36 for six in the Taco. Gone are the days of the $20 tune up.

Inquiring minds want to know where you read that. It's in the FSM and the Haynes manual.

 

$18 Denso K16TR11 Spark Plugs, Pack of 4

Denso K16TR11 is not Iridium.

 

From what I recall, it used to be that those Denso's where actually cheaper straight from the dealership. I run the NGK option so I can't say if that's still the case.

 

No problems with current day single electrode spark plugs - spark plugs have improved in the last 30 years.

 

I have single electrode iridium’s on my 4Runner, no noticeable difference in mpg or running condition.
I’ll get about 20mpg with my 320k mile motor.

 

quite interesting!

 

If the

$18 K16TR11 Spark Plugs, Pack of 4

K16TR11 are the right plugs for yours, then those Denso iridium TT are not the right gap. The Denso Iridium Power are the ones that meet the spec. I don't know if the gap difference is enough to matter though.

 

What is the benifit to using those plugs? Do they cost less, last longer, better performance?

 

Iridium plugs will last longer than copper, But it is a less conductive metal.
I have run them about 100k miles in my Tacoma before it was supercharged, and they looked perfect.
I went with single-sided iridium for my water, mostly because I like them in my Tacoma, but honestly didn’t realize that the 3.4l plugs were dual ground strap.
I’m not an engineer, but I would guess that the dual strap in OEM plugs are because as said above, each cylinder sparks twice per cycle, every time the piston is at top dead center, regardless of compression stroke or not.
Dual grounds will wear slower, Iridium will also wear slower.

 

It's possible that you bought counterfeit spark plugs. It's apparently a thing now this day and age.