Drivers side spark plugs much more worn than passenger side

Just thought I'd share these photo's. The whole job took longer than I thought, really tight spaces in the left bank. I found it odd the drivers side was so much more worn out. Any thoughts?

2017 Taco Sport with 154,000 kilomooses on it. First plug change, I should have done them at 100k.

 

Were all plugs torqued correctly? Also, are you the original owner? If not it is possible the original owner change the 3 on the passenger side but not the driver side.

 

Drivers side is the more difficult side, but why the hell would you bother doing just 3? maybe a DIY, gave up, then forgot about it?

 

That is what I was speculating. Nobody would only want to change the 3 plugs on the passenger side. If the OP is not the original owner, that person may have started changing plugs and just gave up.

 

Interesting. The iridium tips are gone on the one set of 3. Haven't seen that yet.

Did it run better after?

You had 96k miles. I've been changing at 80k miles twice now and see nothing close to that.

 

I concur previous owner tapped out on complication.

 

Due to the Taco lean.

 

None of the plugs were loose. I'm the original owner. Truck has always run fine.

 

Are they different brands? Factory OEM practice has been Denso on one side KGK on other for 1st and second generation, no idea if they continued this for 3rd gen. Could have been a mfg. difference or bad batch.

 

Wow. Surprising. For comparison, the conventional Denso plugs on my truck didn't look that poor when I changed them with 115,000 mi (185,000 km) on them.

 

Scocar the third gen went to iridium plugs, second gen were copper with the denso on the one side and NGK on the other. Had something to do with them trying to get around the smog regulation. When I went to get spark plugs at the dealer for my 2015 they said they only stocked denso and not NGK and had never put the NGK back in as it wasn’t required up here.

 

I can't begin to say what it might be, but something is amiss here.
IIRC, I changed my iridiums @ 120K (miles) and all six looked like they could have gone another 80K.

I believe @bigoldbeef has over 410K on his truck, having only changed the plugs twice. Once @ 200K, and a second time @400K.
Again, miles, not kilometers.
He has contradicted himself with the numbers from one post to the next, but nonetheless, 400K+ with 2 plug swaps somewhere in between.

 

It’s from a shitty tech that only changed one side & said he did all 6. Welcome to the dealership!

 

OP's 1st post says original owner, FIRST plug change.

Either way, @ 95K, the three bad plugs should look like the three good plugs.

 

Sorry it didn’t say original owner that first post…just saw it a few posts down

 

Yeah I know I have a 2015. Conventional wisdom on 2 different brands has been factory vendor supply chain business economics in Japan. Smog regulation is bs, the 2 different brands are exact same spec. No brand of spark plug is required by anyone for any reason. 3rd gen is totally different engine.

My thought was that in this case, the plugs may had been different brands, and hence totally different batches at totally different facilities, one of those being substandard and wearing prematurely.

 

Same brand of plugs. I thought maybe a fueling issue. It seems to run about the same after changing them.

 

Something's not right, and depending on what the problem is, it may not limit itself to the plugs.
The plug coloration looks fine, but if it were my truck, I'd at the very least be looking for answers.
Those plugs look like what I'd expect to see at 200K (miles)

There are some knowledgeable folks here, hopefully one will chime in.

 

Is it possible that the iridium tip is actually more of a rod than a triangle/dome, and the other part just melted?

 

No, the iridium tip is exactly that. It's just the tip that's welded to the core, and it's gone from from these three plugs.
It's not a rod or dome, just the itty bitty tiny, and this case, missing tip.

If these weren't the original plugs, I'd have bet my left nut against a dollar, those three were ebay iridium fakes.