Spark Plugs Driving me Crazy!!!

[t4rnit]

Hi Newbie here.

Got a used 2005 4 V6 at 7Ok. Never had issues except for the Sulfur TSB, that was taken care of. Now at 75k I decide to check the spark plugs a little late from lack of time.

Today will be the 3rd failed attempt to change spark plugs!!!

1st Attempt was unknowingly trying to install Denso Double Platinums. The truck worked for a small duration of time, but eventually would idled out of control and misfire.

BTW. Original spark plugs where still in the car! Half Denso and half NGK.... The spark plugs didn't look too bad either.

SO

The 2nd Time Before reading into detail like I should have, and not wanting to give up on the double platinum, I re-installed the same plugs making sure the .044 gap specification on the plugs where correct.

But once again, FAILED. I returned the plugs and decided to use the originals once again to see if any changes arose, NOTHING..... The truck ran fine with NO ISSUES.

So today was my 3rd Attempt. An attempt based off opinions from Toyota Dealers, Toyota Foremans and Service Managers, Mechanics, Auto Part Shops, and Tacoma.com. Everyone said the same. OE recommendation is best for the 4rth Gen.

Toyota Service manager and foreman stated, "Most problems we see are customers that come in 4runner's that misfire have aftermarket spark plugs. The Foreman gave me a long description to why the iridium would not be a good choice even though I have read otherwise.

Anyhow. From everyone I have spoke to for the exception of some threads on here where people say they use the NGK/DENSO Premium Iridium etc...

I just wanted to perform a simple spark plug change as i have hundreds of times with other cars in the past....So to avoid issues or conflicts, I decided to just go with the Original Denso K20HR-U11's

And to my surprise, The car still responds in the way. Low RPM or the car dies at idle. Shaky and unstable. I thought possible faulty spark plugs, but twice in a row???

Whats going on here?
Help Someone! I don't want to run on these 30k spark plugs forever! :wow:

 

[K.C.]

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[zstampe]

You said a couple times "the four" what do you mean by the four?

 

[Doozi]

I think that something else has to be wrong. I replaced my factory plugs at 71k miles with Autolite XP Iridium plugs and have had no problems at all. Factory calls for a 0.043" gap and the worn original plug gaps ranged from 0.053" - 0.060". The new XP's came out of the box with a 0.044" gap so I just left them at that. I noticed a slightly smoother idle and it seemed a little smoother under hard acceleration.

Have you tried disconnecting the battery to reset the ECU?

And yes, if you only replaced "the four", you need two more!

 

[klennop]

Maybe you have a coil going bad or something?? I personally think it sounds like something other than your plugs. Have you tried cleaning your MAF sensor, I would try that, it is a cheap option to try.

I also didn't think you were supposed to gap Iridium plugs because you can damage the tips of the plugs. So could you have damaged the tips by checking the gap, all it takes is a scratch.

 

[ky_runner]

"Never had issues except for the Sulfur TSB, that was taken care of."

Out of curiosity, how did you resolve the sulfur issue? May be a catalytic converter issue. Just a thought.

 

[SkylineGTRracer]

Normally with iridium's their ready to go outta the box. If you do gap them you DO NOT use that coin thing for gapping. To me it sounds like you got a bad coil.

 

[t4rnit]

"Never had issues except for the Sulfur TSB, that was taken care of."

Out of curiosity, how did you resolve the sulfur issue? May be a catalytic converter issue. Just a thought.

Yes, That's the issue exactly.

I took a printed TSB for the 4Runner (1GR–FE) from online and went into the dealership with it. At first, they tried telling to switch my brand of gas OR to close the back window while driving when I didn't show the TSB, as soon as I showed them it, They ordered the parts right away.

Make sure they order the updated catalytic converters parts and not the old ones.

AS stated on the TSB

"The original part numbers (17410–31450 and 17450–31030) are currently used in vehicle production and are still available as service parts. The repair part numbers (17410–31600 and 17450–31060) should only be used when the customer complains of sulfur dioxide odor."

By the way, if you truck is over 80k forget about it, and if not take it in! I'm glad I took care of the situation before hand. It was a $2,300 fix! :bigok:

 

[t4rnit]

Normally with iridium's their ready to go outta the box. If you do gap them you DO NOT use that coin thing for gapping. To me it sounds like you got a bad coil.

I installed the original not the iridiums.

If it was a bad coil. Wouldn't my car do the same when the old spark plugs are installed?

For some reason, when I install the old half NGK and half Denso, There are no issues! and the car runs fine?

 

[t4rnit]

Maybe you have a coil going bad or something?? I personally think it sounds like something other than your plugs. Have you tried cleaning your MAF sensor, I would try that, it is a cheap option to try.

I also didn't think you were supposed to gap Iridium plugs because you can damage the tips of the plugs. So could you have damaged the tips by checking the gap, all it takes is a scratch.

How would I go about cleaning the MAF sensor? I didn't use iridium, Just the OE Denso's.

 

[t4rnit]

I think that something else has to be wrong. I replaced my factory plugs at 71k miles with Autolite XP Iridium plugs and have had no problems at all. Factory calls for a 0.043" gap and the worn original plug gaps ranged from 0.053" - 0.060". The new XP's came out of the box with a 0.044" gap so I just left them at that. I noticed a slightly smoother idle and it seemed a little smoother under hard acceleration.

Have you tried disconnecting the battery to reset the ECU?

And yes, if you only replaced "the four", you need two more!

I Wish I can say the same thing. Changing spark plugs have never been so brain racking! I did reset the ECU. I tried checkin on here and noticed members say to reset the idle. I have no idea how to do that on the truck.

Any tips?

And I think I confused some member here when I said the "4" I meant the 4runner. :lmao:

 

[t4rnit]

You said a couple times "the four" what do you mean by the four?

Meant the 4runner :banana:

 

[zstampe]

Meant the 4runner :banana:

Ha ha just making sure you didnt only do 4 plugs.

Good luck with a fix man.

 

[klennop]

How would I go about cleaning the MAF sensor? I didn't use iridium, Just the OE Denso's.

Here is something I found on cleaning the MAF, I would try this first, like I said earlier:
http://www.toyota-4runner.org/maintenance/21703-maf-sensor-cleaning-improve-gas-mileage.html

As far as the plugs, if they are Denso's, I think they still have an iridium tip that can be damaged. Even if they are platinum tip, you are not supposed to gap or touch them. Don't touch the gap on the plugs next time because then you can rule out the plugs as a culprit.

Also to comment on the coil issue, it could be a coil acting up which is on its way out? So it may not be consistent.

 

[t4rnit]

Once again. Double checked the Denso's. Me and a buddy of mine that who has a 4runner as well and has done a spark plug swap on his car with no issues. Decided to try once again.

Again. Correct gap, There was no apparent damage to the SP tips. Everything was torqued correctly.

Idle ok on park. Once I hit drive the rpm gage drops from the normal 600 to 500 to 300 to almost dead...... Driving seems normal, But I cant stop without the car without the engine idle dropping at a ridiculous amount....

I cant figure out whats going on! So i guess no car till Monday when I get it scanned. I refuse to put the original spark plugs back in the car. This makes no sense, there goes my weekend!

Anyone who has had similar problems ever come to a conclusion? I know that I am not the only person who has dealt with this. I have read this issue on similar threads with no end result.

HeLp!

:roadkill:

 

[t4rnit]

Here is something I found on cleaning the MAF, I would try this first, like I said earlier:
http://www.toyota-4runner.org/maintenance/21703-maf-sensor-cleaning-improve-gas-mileage.html

As far as the plugs, if they are Denso's, I think they still have an iridium tip that can be damaged. Even if they are platinum tip, you are not supposed to gap or touch them. Don't touch the gap on the plugs next time because then you can rule out the plugs as a culprit.

Also to comment on the coil issue, it could be a coil acting up which is on its way out? So it may not be consistent.

Checked out the MAF sensor. Looked Clean w no constrictions.

:moping:

And for the gapping. I actually re-gapped the original spark plugs when I put them in again. The same way as I did with the new ones. Except the old ones I had to push down because the gaps were at .050-0.054. Still The car worked perfect with no issue, on the old sparks.

So I can't see gapping the plugs really making any damages.

Also from checking the MAF sensor, We checked for vacuum leaks with starter spray. Nothing. Cleaned the throttle out a bit, nothing...
Is my 4runner going crazy or what?

Old spark plugs work, And New ones don't at all... I am almost on the verge of installing half NGK and half Denso's just to see the outcome!

 

[klennop]

Checked out the MAF sensor. Looked Clean w no constrictions.

:moping:

And for the gapping. I actually re-gapped the original spark plugs when I put them in again. The same way as I did with the new ones. Except the old ones I had to push down because the gaps were at .050-0.054. Still The car worked perfect with no issue, on the old sparks.

So I can't see gapping the plugs really making any damages.

Also from checking the MAF sensor, We checked for vacuum leaks with starter spray. Nothing. Cleaned the throttle out a bit, nothing...
Is my 4runner going crazy or what?

Old spark plugs work, And New ones don't at all... I am almost on the verge of installing half NGK and half Denso's just to see the outcome!

So you put the old ones in and then the truck runs fine? If that is the case, then you definitely damaged the new plugs. You may not see any damage you have done but you are NOT supposed to mess with the gap on higher end plugs.

Are you sure you have the correct plug numbers? Sounds stupid simple but I would double check. Check on NGK's site.

I was also thinking a vacuum leak after reading your most recent post but it HAS to be your plugs.

As for the MAF, for the future, you may not see anything visibly but it still may be dirty.

 

[t4rnit]

So you put the old ones in and then the truck runs fine? If that is the case, then you definitely damaged the new plugs. You may not see any damage you have done but you are NOT supposed to mess with the gap on higher end plugs.

Are you sure you have the correct plug numbers? Sounds stupid simple but I would double check. Check on NGK's site.

I was also thinking a vacuum leak after reading your most recent post but it HAS to be your plugs.

As for the MAF, for the future, you may not see anything visibly but it still may be dirty.

I read this somewhere on another thread and a few others as well...

These have the wrong gap, but can be gapped to fit:
Denso Platinum TT PKH20TT 0.040"
Denso OE Copper K20HR-U11 0.044"

These have the wrong gap, but shouldn't be manually gapped:
Denso OE Iridium SK20HR11 0.043"
Denso Iridum Power IKH20 0.043"
NGK Iridium IX LFR6AIX-11 0.044"

DO NOT ADJUST THE GAP ON IRIDIUM PLUGS IF YOU CAN AVOID IT! It is extremely easy to crack the iridium coating on the electrode and ruin the plug. Copper and platinum can be gapped manually, on iridium you shouldn't. If you have an iridium plug with incorrect gap (other than listed), return it as defective and get another one.

- I got the Denso OE Copper K20HR-U11 0.044....
So basically adjustment I thought should not be an issue on this plug? Right?

 

[klennop]

I can't speak from experience on the Denso's, gap amount etc. I just know from messing with gap and different plugs in my 2-stroke stuff that it is super easy to damage the high end plugs without you knowing it.

I went with the NGK Plugs Iridium plugs in my truck, put them in and everything is all good.

I would suggest picking up some of the NGK plugs, don't touch them, gap, etc., put them in see if you have any problems. I bet everything will be good.

 

[jbx35]

Replaced my OEM's on my 08 (34k miles) with NGK (6619) LFR6AIX-11 Iridium IX Spark Plug. Noticable improvements; straight from the box. More responsive, smoother idle and better gas mileage.