Oh wowwww. My truck had 3 improper spark plugs installed prior!

Alright, so I have a 2002 Tacoma TRD 3.4L. I just bought it a month ago, but due to waiting on the title to come in and the holidays am really just now driving it. I took it into the shop earlier today to get it PM'd. They talked me into changing the spark plugs and boy am I glad they did. 3 out of the 6 spark plugs were not the correct ones. The ones on the driver side were single point plugs and the ones on the right side were the proper double sided ones.

The truck now has the proper spark plugs to operate in it which is great, but I am now wondering how long it was operating with the wrong plugs and has it caused damage. What type of damage could it have caused, and how would it manifest itself.

Thanks.

 

Calm down that by itself wouldn't cause any damage. If they were hotter plugs they could eventually do some damage though. Did you keep the old ones so you could lookup exactly what they were?

 

I just replaced the plugs in my newly purchased 02 4runner 3.4L. All 6 plugs were regular NGK's and i installed the correct doubled sided densos. You should be ok as long as the plugs were the same in lenght. If it's running fine i'm sure you'll be ok. Congrats on your purchase!

 

I'm surprised it hasnt spun a bearing by now.

Unlike many others on this site, I dont believe the dual electrode hype. I have never used them. 50k miles without a single issue or difference in performance.
You truck is fine.

 

OP, the truck came from the factory with the two different style plugs.

 

What everyone else said.

Think of it this way. There must be a million variables that can influence the quality of ignition in one cylinder vs another. If a different quality of ignition in one or more cylinders could damage an engine ... there would be very few cars on the road.

No need to lose sleep on this.

 

I almost said above that I wondered if Toyota did that on purpose. I believe that some cars are purposefully set up with some cylinders different than others????? But I want sure???

 

LOL. Guess the OP screwed up his engine by using the wrong plugs. JOKING

 

Some did an some didn't. My 03 had the same plugs all the way around.

 

So basically it's irrelevant then. Good to know.

 

I see what you did there.

 

There are two different brands in the 4L same plug different manufactures. Who knows OP may have shortened the life of your engine by a couple hundred miles out of 300K. In other words don't loss sleep over it.

 

This^^^.

 

Not sure? Did Toyota do it? Did they have a good reason to do it?

Can't imagine you ruined your truck by using wrong plugs. Still, it would be good to know why they are how they are, if these posters here are right?

Maybe it's worth a call to a Toyota dealership mechanic directly and ask?

 

Awesome! Fascinating.

Could end up being as simple as phasing out old inventory for a new type of plug?

So, I wonder if it's only on a few trucks during such a theoretical transition, or if it is on all, as in designed?