57k and half the Irridium plugs are eroded, half look good

If they were gapped the dealer fucked up. If they used a standard gapping tool which I'm almost positive they did, they rubbed the iridium coating off the tip of the plugs which essentially rendered them useless as an iriduim plug. They become at that point as good as a copper which may explain why they were worn out and look like a copper plug.

 

It isn't iridium coated, the electrode tip is solid iridium so the common mistake is breaking the tip off completely, which could have happened to 3 plugs if the installer was totally retarded. Iridium plugs should be accurately pre-gapped with no reason to gap.

 

Toyota only specifies Iridium on the 2.7. 100k change interval.
The 4.0 gets copper from the factory. 30k change interval.
Check your manual.

IF you had Iridium in there, it's because the dealer installed them with the supercharger, but when it rolled off of the line, it had copper.

 

Do not do this. The Iridium plugs were installed with the supercharger. If I remember correctly they fire at a lower temp. This lower temp helps stop premature detonation or some such. The only reason I know this TexasPreRunner is that I have a supercharger. Is Texas its own state yet? Did they have to remove the Supercharger to remove drivers side plugs?

 

I remember somewhere on this forum i read that toyota actually uses two types of plugs one the v6 (One on one side and one type on the other).If i find it i will post a link.

 

Factory plugs on the V6 are copper NGK on one side and copper Denso on the other. There is no logical reason for this other than Toyota dual-sources their plugs to help immunize themselves from shortages caused by problems with one supplier or the other.

If the dealer changed plugs with the SC installation, that would have been nullified (unless perhaps they neglected to change one bank).

 

http://www.tacomaworld.com/forum/technical-chat/30479-how-spark-plug-change-1-gr-fe.html

 

OP said dealer told him they came from both sides?

 

Wondering if the tech that installed the SC didn't neglect to upgrade the plugs on one bank, leaving him with 3 new Denso iridium and 3 factory Denso copper (which are the 3 that went bad).

OP, what's the part number on the bad plugs?

 

Ya, looking at the picture, even taking into account that one plug is brand new and the other is old, they are definitely not the same plug. The insulator shape is different, and the new iridium electrode has a conical taper that begins well below the edge of the insulator. The eroded plug, if it ever had a taper, begins above the insulator.

That's a copper plug.

 

Then no they didn't come from both sides if you are right. Does make more sense.

 

Iridium plugs come in bag "K" of the Supercharger kit. I am thinking if where this thread is going and that those are copper plugs then dip ship mech. forgot to install Iridium plugs. Even worse when install was done he/she would have had 3 iridium plugs from bag "k" left over and said F it and sent the truck out the door. Probably from drivers side. Did OP take it to same dealership with bad code that did install?

 

One plug has never been in an engine it looks fine because it is, the other one is way past overdue for replacement. There is nothing wrong with the old plug other then the fact it is way beyond worn out. Want to do a comparison lay 6 used plugs on the table then take a picture.

 

Waiting for Arizona to jump on the bandwagon

 

I definitely agree with the plugs being pregapped with no need to gap them.

 

Always use a feeler to double check them before you install. Always.