210k miles on original plugs!

[jeremyc74]

So I've had a set of plugs and wires to put on laying around for a while, but I've just been too busy traveling for work to get it done. I'm headed out on a long road trip tomorrow, and the 4Runner had started to develop a very slight miss occasionally so I decided to get 'er done today.

I pulled the plugs on the passenger side, and they were NKGs and in pretty bad shape so I was feeling good about this correcting the issue. When I pulled the first plug out of the driver's side, it was a Denso, so in all likelihood these are the plugs the truck left Japan with in 2000. :suspicious:

The crazy part is the truck was still running fine, up until my last trip home from VA about a month ago. Gas mileage was still up around 17.5MPG, which I knew was a little low but I just attributed it to tires and the fact that I'm usually doing about 80MPH.

I'm headed to NC tomorrow for a day, and then on to VA, so I'm very interested to see what the mileage looks like with the new plugs. I wish I had checked it a little closer on the last trip home so I'd have better numbers to compare it to.

 

[JayRolla]

So I've had a set of plugs and wires to put on laying around for a while, but I've just been too busy traveling for work to get it done. I'm headed out on a long road trip tomorrow, and the 4Runner had started to develop a very slight miss occasionally so I decided to get 'er done today.

I pulled the plugs on the passenger side, and they were NKGs and in pretty bad shape so I was feeling good about this correcting the issue. When I pulled the first plug out of the driver's side, it was a Denso, so in all likelihood these are the plugs the truck left Japan with in 2000. :suspicious:

The crazy part is the truck was still running fine, up until my last trip home from VA about a month ago. Gas mileage was still up around 17.5MPG, which I knew was a little low but I just attributed it to tires and the fact that I'm usually doing about 80MPH.

I'm headed to NC tomorrow for a day, and then on to VA, so I'm very interested to see what the mileage looks like with the new plugs. I wish I had checked it a little closer on the last trip home so I'd have better numbers to compare it to.

No much spark is needed for no boost and low compression applications. Im not surprised at all.

 

[jeremyc74]

No much spark is needed for no boost and low compression applications. Im not surprised at all.

I'm mainly surprised that the previous two owner never bothered to change them in 160k miles.

I'm happy to report that it made a huge difference in the way the truck pulls up top. I was almost afraid I was having a transmission issue, because the misfire would happen when it would drop down to 3rd on the interstate, and it kind of felt like the transmission was slipping. That doesn't seem to be the case though. It's much better now.

 

[98WhiteT4R]

damn thats pretty cool that they lasted that long and don't look like complete sh*t

 

[JayRolla]

I'm mainly surprised that the previous two owner never bothered to change them in 160k miles.

I'm happy to report that it made a huge difference in the way the truck pulls up top. I was almost afraid I was having a transmission issue, because the misfire would happen when it would drop down to 3rd on the interstate, and it kind of felt like the transmission was slipping. That doesn't seem to be the case though. It's much better now.

Yeap, known issue. Almost 90% of people with the "my trans feels like its slipping on highway" is just a misfire.

 

[jeremyc74]

Yeap, known issue. Almost 90% of people with the "my trans feels like its slipping on highway" is just a misfire.

Yeah, I started thinking that was all it was after I turned of OD and ran it through that same RPM range without a downshift and could still feel it. I'm glad it seems to be nothing more than plugs. In my experience with N/A motors it's pretty rare for the plugs to cause a noticeable miss even when they're in bad shape, but obviously these were completely shot!:doh:

 

[David_S]

Wow, awesome of the truck to just keep on chugging along. Wonder if someone started the job, got distracted half-way and forgot. Maybe they thought they finished and threw 3 new plugs and 3 old plugs into the trash.

That being said, see if you can at least inspect your timing belt, idlers/pulleys. You obviously know your vehicle better than I do, but those plugs show a potential lack of maintenance.

This thread seems to be pro-changing the timing belt.
http://www.toyota-4runner.org/3rd-gen-t4rs/107005-when-change-timing-belt.html
This thread seems to be anti-changing it. Also has a link to a Yota-tec article within it.
http://www.toyota-4runner.org/3rd-gen-t4rs/44672-timing-belt-failure.html

Keep her on the road till the wheels fall off!

 

[jeremyc74]

Wow, awesome of the truck to just keep on chugging along. Wonder if someone started the job, got distracted half-way and forgot. Maybe they thought they finished and threw 3 new plugs and 3 old plugs into the trash.

That being said, see if you can at least inspect your timing belt, idlers/pulleys. You obviously know your vehicle better than I do, but those plugs show a potential lack of maintenance.

!

These trucks came from the factory with 3 NKG plugs on one side, and 3 Denso on the other. Toyota used both suppliers and that's how they divided them up.

I did the timing belt at 200k. It had been changed at least once, but I suspect it had been in there since the 80k service. The couple I bought it from didn't do much to keep it up, so I've spent the last two years taking on one major project at a time and now I'm just about finished. I started with the suspension, and put the plugs lower on the priority list because they won't generally cause an accident or leave you stranded on the side of the road. :crutch:

 

[BoarderDave]

Nice! Good to know.

You just reminded me that I need to go through my previous owners receipts and see if mine were ever done before me (bought from Original Owner). I should do mine pretty soon too. I wouldn't be all that surprised if I come to find the same situation as you. However, mine only has 157k on it right now.

What type of plugs and wires did you replace it all with? The usual recommendation found on here...?

 

[LittleCaesar]

Probably could have regapped them and been fine. How big was that gap?

Looks like one healthy engine to me.

Do the wires as well?

 

[jeremyc74]

Nice! Good to know.

You just reminded me that I need to go through my previous owners receipts and see if mine were ever done before me (bought from Original Owner). I should do mine pretty soon too. I wouldn't be all that surprised if I come to find the same situation as you. However, mine only has 157k on it right now.

What type of plugs and wires did you replace it all with? The usual recommendation found on here...?

Yeah, Denso plugs, and OEM wires. I figure these lasted 200k, why even bother with aftermarket?

Probably could have regapped them and been fine. How big was that gap?

Looks like one healthy engine to me.

Do the wires as well?

The gap was probably .200"! I was pretty happy with the coloration on the plugs. They all looked even, and looks like it was burning clean. I guess it had to be for them to last that long. Yeah, did the wires and the PCV valve while I was in there, an oil change, tire rotation, and checked the rear diff fluid.

I was planning on holding off on the plugs until I had time to do the valve cover gaskets, but with the misfire cropping up I decided not to wait.

 

[gamefreakgc]

I've never seen an electrode shaped like that, tt has contour, so odd. Then again I've never heard of spark plugs lasting 200,000 miles lol! I guess there's something to be said for the dual-ground system.

 

[nevada]

So I've had a set of plugs and wires to put on laying around for a while, but I've just been too busy traveling for work to get it done. I'm headed out on a long road trip tomorrow, and the 4Runner had started to develop a very slight miss occasionally so I decided to get 'er done today.

I pulled the plugs on the passenger side, and they were NKGs and in pretty bad shape so I was feeling good about this correcting the issue. When I pulled the first plug out of the driver's side, it was a Denso, so in all likelihood these are the plugs the truck left Japan with in 2000. :suspicious:

The crazy part is the truck was still running fine, up until my last trip home from VA about a month ago. Gas mileage was still up around 17.5MPG, which I knew was a little low but I just attributed it to tires and the fact that I'm usually doing about 80MPH.

I'm headed to NC tomorrow for a day, and then on to VA, so I'm very interested to see what the mileage looks like with the new plugs. I wish I had checked it a little closer on the last trip home so I'd have better numbers to compare it to.

Probably could have regapped them and been fine. How big was that gap?

Looks like one healthy engine to me.

Do the wires as well?

I changed plugs on a ford Taurus last year. it had something like 300k....original plugs. still ran good, still got great mileage. the gap was HUGE.

its amazing what our modern ignitions will do.

 

[jeremyc74]

Averaged about 18mpg over the last three tanks, and most of that is with the A/C on and doing close to 80MPH. I'd say it's at least .5mpg better, but probably closer to 1 since I hadn't really checked it in a while. It is also noticeably smoother when it drops into 3rd gear on the interstate with the cruise set. I'm kicking myself in the ass for not doing these a year ago. :washing: