Award for worst Spark Plug?

Just bought a 2012 Tacoma PreRunner V6 RWD with 120k miles on it. Changed the spark plugs this weekend. Does this win any awards for worst spark plug? By the way, the performance now is night and day. I really can't believe the difference.

 

I’ve seen plugs with the electrodes almost completely gone before. Hard to believe that the engine would still run!

 

Factory original?

 

I would say that depends on the last time they were changed.

 

I have all the service records from the dealer. Regular oil changes since it was new but no history of any spark plug changes so yes I believe these are the factory original plugs with 120k miles on them.

 

You could check and see if half are Denso and the offer half NGK. Don't know why they did it or what years they did it for exactly but I know a lot of second gens came with half and half from the factory.

 

A month ago, I bought a 107k Taco with no service records outside the included CarFax. I'll try to get to the plugs next weekend and even though my evidence will be anecdotal, I'll let you know what I find. I've been curious and your post reminded me, but I've been way too busy to check since I got it.

Maybe I should spend less time on TacomaWorld and more time under the hood!

 

It can hard to judge a plug from a photo, but I'd say the engine they came out of may have worm valve stem seals or valve guides.

 

This is a top contender

 

I'm afraid I'd be inclined to do a compression and leakdown test on that motor.

And likely a top end cleaning.

No doubt about it running better!

 

The award for worst spark plugs is being stranded and waiting for a tow truck.

 

Can you explain what might make you think that? I'm not a mechanic so I don't understand the potential correlation. What would be the other symptoms?

All 6 were Denso branded spark plugs by the way.

 

Yup, this was the case in my 2009 when I swapped out for new. I was confused why the Haynes manual said to use one of the two companies, then I saw that the truck had different brands on each side. That made me even more confused...

 

I'm not having any typical symptoms of low compression such as running rough or stalling. In fact, the engine is running much better now with ample power upon acceleration after the new plugs went in. I'll need to check into a top end cleaning. Are there any DIY videos for this on the Tacoma V6?

 

Lots of black soot all over the spark plug...either oil or engine running very rich. Looks more like oil to me. You could also have worn oil rings on pistons(see Clearwater Bills comments). Whatever the case may be, that is not what plugs look like that come from a properly running engine.

Photo in upper left hand corner shows what a well-worn plug looks like.

 

without knowing the plug #, it doesn't look like a factory plug. i could be wrong.

 

Best explanation I've seen as to why Toyota used two different brands on the V6 is that Toyota is part owner of both companies. Our 07 Lexus V6 came with Iridiums on all plugs; although I don't remember if NGK or Denso. Don't know why only the Tacos were split this way.

But yes, those plugs have too much oil residue. Check your oil level every 1K to make sure the engine doesn't run out. Opinions range ... generally speaking, if engine burns/uses/losses more than a quart every 1K, engine should be repaired. Going up a weight may help; if you use 5/30, go up to 10/30, etc...

 

The worst spark plugs are the kind that break apart in the head. Lots of fun to get those out.

 

While we are in the topic of spark plugs, can some a few of you knowledgable share
what you think are some really good, very good, and best spark plugs for our trucks?
I know there's a lot of snake oil in the spark plug industry much like the in speaker cables industry out to profit on people's ignorance,
that said, what are some of the good ones that high end vehicles use? (compatible ones of-course)

 

The Ford Triton forum is down the hall and to the left..