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Discussion Starter · #1 ·
I get a cylinder 2 misfire code about twice a month. Recent plug change (Champion 7034, 3 months ago) didn't help. The engine runs fine, no evident problems. Any opinion on whether Seafoam in the intake would possibly help? I thought about trying that, then throwing some Autolite APP985s in, then a new coil rail. If those things don't do it, then it could get expensive and interesting. Any other ideas?

It's a 2005 X, 4.0
 

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HEEEEEELP!!!! 2000 wrangler sport

I get a cylinder 2 misfire code about twice a month. Recent plug change (Champion 7034, 3 months ago) didn't help. The engine runs fine, no evident problems. Any opinion on whether Seafoam in the intake would possibly help? I thought about trying that, then throwing some Autolite APP985s in, then a new coil rail. If those things don't do it, then it could get expensive and interesting. Any other ideas?

It's a 2005 X, 4.0
i got the same code. i replaced plugs, coil rail, #2 fuel injector which had fuel to it, but replaced it anyway, ive changed batteries ( it died) reset the code, light still pops on and stays, truck starts up fine but idles rough and has hesitation and no power when accelerating. Now im out of $$$$$$$$. good luck to you
 

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Have either of you tried to change plug wires?
 

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Maltese said:
Have either of you tried to change plug wires?
If they have coil rails, they don't have plug wires. Newer TJ's....

How is it acting with the misfires? Is it noticeable, or just a code? Have you checked the o-rings around the fuel injectors where they meet the engine for leaks? How's the exhaust smell? No long starts? If all that is ok, I'd lean towards it being sensor related.
 

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"""""I'd lean towards it being sensor related. """""

What sensor is specific to one cylinder and not all cylinders?


Temp? MAP? CPS? O2?
 

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Discussion Starter · #6 ·
If they have coil rails, they don't have plug wires. Newer TJ's....

How is it acting with the misfires? Is it noticeable, or just a code? Have you checked the o-rings around the fuel injectors where they meet the engine for leaks? How's the exhaust smell? No long starts? If all that is ok, I'd lean towards it being sensor related.
Mine seems to be running fine. The code usually pops up when I make a quick stop somewhere and only have the engine off for a few minutes. No symptoms at all. It is always the same code (same cylinder). I'm kind of worried it might be a weak valve spring or something like that. Not worried enough to do a valve job if it is, though. Like I said, it seems to be running great. Don't see how it could be a sensor, since it is a cyl 2 misfire.

I'm thinking seafoam first, then injector, then rail. That's after I check to see if a plug is fouled. I had this code pop up before I changed the plugs the last time (Champion 7034s), and it didn't come back for 3 months. Lately, it's once or twice a month.
 

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rrich said:
"""""I'd lean towards it being sensor related. """""

What sensor is specific to one cylinder and not all cylinders?

Temp? MAP? CPS? O2?
The 2nd time my TPS went bad, I'd get misfire codes on cylinders 1 and 2 after it would buck on acceleration from a stop. Sounds fitting to me for the second post. I'd have multi-quoted, but I'm on my phone at work. Just trying to help.
 

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teknoid said:
I get a cylinder 2 misfire code about twice a month. Recent plug change (Champion 7034, 3 months ago) didn't help. The engine runs fine, no evident problems. Any opinion on whether Seafoam in the intake would possibly help? I thought about trying that, then throwing some Autolite APP985s in, then a new coil rail. If those things don't do it, then it could get expensive and interesting. Any other ideas?

It's a 2005 X, 4.0
Not sure if it would help your issue or not, but I'd use Mopar Combustion Chamber Cleaner before I used Seafoam again. I think it was on this forum that had a good thread on it. Might read that then decide.
 

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teknoid said:
Mine seems to be running fine. The code usually pops up when I make a quick stop somewhere and only have the engine off for a few minutes. No symptoms at all. It is always the same code (same cylinder). I'm kind of worried it might be a weak valve spring or something like that. Not worried enough to do a valve job if it is, though. Like I said, it seems to be running great. Don't see how it could be a sensor, since it is a cyl 2 misfire.

I'm thinking seafoam first, then injector, then rail. That's after I check to see if a plug is fouled. I had this code pop up before I changed the plugs the last time (Champion 7034s), and it didn't come back for 3 months. Lately, it's once or twice a month.
I'd say checking the plugs is the right first step. See if they are all fouled or just #2 (or none). Were the ones you changed 3 months ago fouled?
 

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Discussion Starter · #10 ·
I'd say checking the plugs is the right first step. See if they are all fouled or just #2 (or none). Were the ones you changed 3 months ago fouled?
They weren't fouled, but looked pretty bad. It was the first time I had changed them since I bought the Jeep. Thinking on it, it's been a lot longer than 3 months. It was one of the first things I did. I was getting under 11 mpg at first. Putting the right temp thermostat in and changing the plugs that were gapped way too small got it to ~16-17. I picked up a set of Autolite APP985 and may throw those in today if the one in cylinder 2 looks bad. I really doubt it's a plug though. It was p0302 before and after the last set went in.

I guess I'll go by the old "replace by increasing cost" procedure. O2 sensor, injector, rail.
 

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P0302

They weren't fouled, but looked pretty bad. It was the first time I had changed them since I bought the Jeep. Thinking on it, it's been a lot longer than 3 months. It was one of the first things I did. I was getting under 11 mpg at first. Putting the right temp thermostat in and changing the plugs that were gapped way too small got it to ~16-17. I picked up a set of Autolite APP985 and may throw those in today if the one in cylinder 2 looks bad. I really doubt it's a plug though. It was p0302 before and after the last set went in.

I guess I'll go by the old "replace by increasing cost" procedure. O2 sensor, injector, rail.
Hey trek ok'd,

Was wondering what came of your your misfire on cylinder #2 did you get it fixed. having same issues with my 06 wrangler. Was wondering if you could point me in right direction to fix.
 

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Good luck my sons 01 wrangler had the same random misfire in multiple cylinders spent a boat load on it and eventually got rid of it.


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I never did figure it out. Spent about a grand at various dealers and not one fixed it. Ended up trading it in.


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I have heard it could be value springs or maybe something internal in the engine. Have changed plugs and coil rail. Might do the same thing you did.
 

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I have heard it could be value springs or maybe something internal in the engine. Have changed plugs and coil rail. Might do the same thing you did.


I replaced plugs, coil pack, cleaned fuel injectors, compression test, fuel pressure test and a list of things I don't remember but nothing helped. I wasn't about to get into having valve springs done to not fix the issue. I got rid of it before I spent anymore in it.


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I was told this is an issue that hits between 40k-60k miles. Basically sounded like a death sentence for the motor. The issue , I am told, is with the cylinder head leaking and the only tell is the engine light. Spark plugs didn't help and it can lead to causing issues with the engine block in the head isn't replaced.

I have a 17 with 36k so no issues yet. I am worried it may come up soon. Any thoughts?
 

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I was told this is an issue that hits between 40k-60k miles. Basically sounded like a death sentence for the motor. The issue , I am told, is with the cylinder head leaking and the only tell is the engine light. Spark plugs didn't help and it can lead to causing issues with the engine block in the head isn't replaced.

I have a 17 with 36k so no issues yet. I am worried it may come up soon. Any thoughts?
Me thinks you speak of 3.6L jk issues when post is in TJ forum about 4.0L. I did the same thing in the JK forum a few days ago about a similar issue only with advice on a 4.0L for a 3.6L misfire.
 

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I was told this is an issue that hits between 40k-60k miles. Basically sounded like a death sentence for the motor. The issue , I am told, is with the cylinder head leaking and the only tell is the engine light. Spark plugs didn't help and it can lead to causing issues with the engine block in the head isn't replaced.

I have a 17 with 36k so no issues yet. I am worried it may come up soon. Any thoughts?
Also, remember that JKs shipped roughly 2x the number of jeeps that TJs did. I know of no one who needed to replace a 3.6L engine in my Jeep club and some of those guys have 200k. If your 3.6L doesn’t have any issues then it may never have any until much later in its life. No need to fret.
 
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