Spark Plug Issues - 2006 Liberty

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spta97

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Hi everyone,

I was hoping to get some assistance with a spark plug issue. I did some research on the internet and it seemed that platinium plugs were reccomended. I changed out the NGK coppers (stock) for the NGK platinums (ZFR6FGP) gapping to .040" as stated on the hood sticker.

Everything went fine but now the ride seems sluggish. When accelerating on the highway you have to give it more gas and it just does not feel as peppy as it was. I was really surprised because the old plugs were dirty and gapped all over the map.

The engine is not backfiring and it starts and runs smoothly, just seems to have lost power.

Any suggestions on what could be going on here? I am tempted to put in the NGK coppers as I do recall hearing a while ago that if the engine uses coppers, stick with them.

Thoughts?
 

Jeepin05

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Honestly haven't read much at all bout others using the NGK Platinum's, it seems everybody runs either the regular NGK's (only good for ~20k) or Autolite Platinums. I installed the Autolite's when I first got the Jeep and it ran great.

Sorry not much help here, but you may want to consider reverting back to the regular NGK's.

I'm sure others will chime in with things you may be able to check. Given that it starts and runs smooth (no SES light), I'm assuming your plugs might be the weak point.
 

spta97

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Honestly haven't read much at all bout others using the NGK Platinum's, it seems everybody runs either the regular NGK's (only good for ~20k) or Autolite Platinums. I installed the Autolite's when I first got the Jeep and it ran great.

Sorry not much help here, but you may want to consider reverting back to the regular NGK's.

I'm sure others will chime in with things you may be able to check. Given that it starts and runs smooth (no SES light), I'm assuming your plugs might be the weak point.

Thanks for the reply Jeepin. I'm tempted to go with the coppers as well but let's see what others say. I heard about the the Autolites as well but I would just prefer to go with the stock ones as they seemed to work fine.
 

rockymountain

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Most people just get Autolite platinums. I did and it ran great. I'm about due for my second change and I'm getting those again. Since you are having problems, I would change them out asap before it hurts something else. Get new plugs and try to return those NGKs if they'll let you.
 

67Customs

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The NGK G-Power (Platinum) plugs in the 3.8L in my Town and Country are working great. I wouldn't think it would be the plugs unless something is physically wrong with them. They are very good plugs.

I put the Autoloite Double Platiunum plugs in the 3.7L on my KJ and they are also working great. Good plugs as well.
 

spta97

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Other than the longer life are there any advantages to going with the Autolite Platinums? I would prefer to just get the stock coppers as 1) they are cheaper, and 2) it would eliminate the plugs as the issue.

My research dictated that the NGK platinums were great plugs but they are not performing great. I worry about spending money (and time) on the Autolites only to have the same issue.

Anything that I could have done wrong that would cause this? I decided to put the anti-seize on the threads (I heard arguments for and against) but torqued them by hand. The little springs in the wires / connectors were all there, and I gapped them all properly.

Could it be that they gave me the wrong part?

Thanks again for allthe replies :party52:
 

Dave

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Double check if those are the right plugs? Is it possible one of those new plugs is bad?? You got no MIL though?


Anyway, when I changed mine I used the copper core NGK's. They were under $20 for 6 at NAPA. Not expensive. You could try them?

Dave
 

spta97

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Double check if those are the right plugs? Is it possible one of those new plugs is bad?? You got no MIL though?


Anyway, when I changed mine I used the copper core NGK's. They were under $20 for 6 at NAPA. Not expensive. You could try them?

Dave

Dave,

No engine lights or any indication that something was wrong.

I just cross referenced the part number on NGK's site and it does list the 2006 Liberty 3.7 liter as an application. The gap noted as OEM on their site is .044" (the jeep has a sticker stating .040". I also noted that some of the newer spark plugs are not gappable - it is set at the factory. Interesting that some of these plugs were notably off though which is why I gapped them.

Perhaps in my attempt to gap them properly I caused damage?

I am leaning towards the coppers for a cheap fix.
 

osufans

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you just answered my only thought, was that maybe you got the wrong plugs....

with no MIL, i'm not sure what else to suggest. do you have the old plugs still? put them back in and see if the issue persists. i was thinking about going to plats myself, but after reading this i'm not too sure now... :)
 

spta97

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you just answered my only thought, was that maybe you got the wrong plugs....

with no MIL, i'm not sure what else to suggest. do you have the old plugs still? put them back in and see if the issue persists. i was thinking about going to plats myself, but after reading this i'm not too sure now... :)

Unfortunately the old plugs are now in a landfill - along with the boxes for the new ones :favorites68:

After seeing the condition of the old plugs (including the varying gaps) I was sure that I was going to get some performance gains. I think I am just going to go with the copper and be done with it.

I won't get time for a couple of weeks but will post impressions once I do.
 

jnaut

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You certainly won't go wrong with the NGK coppers. If you're looking for a rapid return to normalcy for the least amount of cash outlay, I'd go back to the coppers.

I too am a little concerned about NGK stating a .44 gap when the 3.7 requires a .40 gap.

BTW, when you regapped them, did you use a plastic gapper?
 

diyman

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Feels like what I'm about to say is the most idiot thing I've ever said in my life but ..... Have You changed the AIR FILTER ????

Don't know why, but I changed my spark plugs last month, OEM NGKs, and real improvement showed up only after changing the air cleaner..
It didn't look like being dirty nor clogged, but I've noticed our KJs are a bit picky on air filters, they prefer clean and tidy ones :shrug:

Maybe the 'poor' platinums aren't the culprits after all.

Also, we could not blame the coils (6) altogether, only thing left is PCM ( shiver... )

Just my 0.02
 

Jeepin05

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You certainly won't go wrong with the NGK coppers. If you're looking for a rapid return to normalcy for the least amount of cash outlay, I'd go back to the coppers.

I too am a little concerned about NGK stating a .44 gap when the 3.7 requires a .40 gap.

BTW, when you regapped them, did you use a plastic gapper?

Same thing I was wondering, whether you used a plastic gapper. Apparently the metal gappers will damage Platinum plugs...
 

Jomac

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BTW, when you regapped them, did you use a plastic gapper?[/QUOTE]

i was told that that was not necessary as long as you are careful and don't bang the plugs around. one would think that if a plastic gapper was required you could find one anywhere. i haven't been able to find one online or at the auto parts stores. this would lead me to believe that plastic gappers are not a must. i used a metal gapper with no ill effects when i installed my autolite double plats.
 

jnaut

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I'm doubting your issue was the lack of a plastic gapper, and I too have never found one in the stores. I bough Bosch Platinum Plus plugs and they were already gapped to .40 so I didn't have to use a homespun method to gap them. My guess is if the metal gapper had caused your problem, the damage to the plug would be pretty obvious.

x2 on the aircleaner. Check that.
 

spta97

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Hey everyone, thanks for the replies. I used a metal gapper on the platinum plugs which could have caused the damage but I did not see anything obvious. I too was not aware that plastic gappers existed but will be on the look out for one.

The air filter was changed a few weeks ago and granted an nice improvement in "seat horsepower" which is why I was hopeful that the plugs would do the same.

In any case, I put the NGK coppers in today (which were all gapped appropriately out of the box) and the Jeep is back to it's normal self :party52:

I cannot say with 100% certainty that I did not cause damage to the platinum plugs prior but will take some pics of them once I get some time. I am just happy that everything is back to normal.

Thanks again for all your assitance!
 

Idaho08KK

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I installed NGK Iridium plugs in my 08 as soon as I got it. No change in power or fuel economy, but I won't have to change them as often as the copper plugs.
 

jnaut

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I installed NGK Iridium plugs in my 08 as soon as I got it. No change in power or fuel economy, but I won't have to change them as often as the copper plugs.

Iridiums... isn't there some info around here suggesting that the KJ can't provide enough juice on the spark with the iridiums?

And weren't we trying to figure out why your jeep got 10mpg? Could there be a link?
 

moparman

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Iridiums... isn't there some info around here suggesting that the KJ can't provide enough juice on the spark with the iridiums?

And weren't we trying to figure out why your jeep got 10mpg? Could there be a link?

That's how I remember it... The spark isn't that hot. My 2 Neons were the same way. The more expensive the plug, the worse they ran.
 

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