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Discussion Starter · #1 ·
Hello,i have an 06 jeep rubicon 4.0 mt .now that I have more or less figured out my mpg problem I have another issue( not as pressing but still). Went out and fired up my jeep to go to work and every thing was fine when the motor is cold and idle is higher but once the motor reaches operating temp and down it starts idling a bit rough. Now it's not kicking on the mil light nor is it wanting to die but it feel like there is a slight misfire or not getting enough fuel or something. I read in another forum that it could be an issues with heat and where the injectors set into the manifold. Anyone else have this problem.
 

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I had something to it on both my jeeps one was an O2 sensor and a tps sensor.. People say O2 sensors are never it just try unpluging it and find out which cylinder is miss firing and then switch the injector if the miss fire moves boom found the problem or also check the coil pack check it at night if u see a blue spark arch its a coil pack
 

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Starting with the basics, how old are your spark plugs? If they aren't that old, exactly what brand & model spark plug did you install?
 

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Discussion Starter · #5 ·
Starting with the basics, how old are your spark plugs? If they aren't that old, exactly what brand & model spark plug did you install?
Plugs are champs 7704 put in a couple of days ago. Also put all four new o2 sensors in with NTK brand. I pulled and cleaned the IAC and ran a bottle of 44k in it. Only real weird thing in all that was when I replaced the coil boots and inner springs, the very front boot spring was hard to pull out so I ended up stretching it and it finally came out. I put the new stuff on and they seemed to fit nice so IDK if I my have damaged it.
 

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Discussion Starter · #7 ·
Update: I went ahead and replaced the IAC and TPS and still did not fix the problem I'm now starting to wonder if my injectors are getting heat soaked
 

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Starting with the basics, how old are your spark plugs? If they aren't that old, exactly what brand & model spark plug did you install?
I'd go with Jerry on this one (because he helped me through a similar issue). I noticed with mine that I had one plug that was gapped just a hair off and caused my misfire. If it isn't your plugs, it could be a heat soak issue. I had to replace the heat shield under the injectors on mine, old and falling apart. I also placed a sleeve around the number 3 injector. I think there is a thread on here with part numbers. The DIS is very finicky I've come to notice.
 

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Discussion Starter · #11 ·
I'd go with Jerry on this one (because he helped me through a similar issue). I noticed with mine that I had one plug that was gapped just a hair off and caused my misfire. If it isn't your plugs, it could be a heat soak issue. I had to replace the heat shield under the injectors on mine, old and falling apart. I also placed a sleeve around the number 3 injector. I think there is a thread on here with part numbers. The DIS is very finicky I've come to notice.
Does that sleeve cover the 06 4.0, I thought it was for the 02-04 models
 

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Not going to say it isn't, but the more common problem with the injector shields was a hot soak problem. After the vehicle was driven, parked for a bit, and then restarted.
Would cause a fuel starvation problem, like vapor lock. Making hard to start, running poorly until enough cool fuel got through the injectors. Can't say I remember it causing a problem in normal driving.

I'm with Jerry, always start with the basics.
 

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Discussion Starter · #13 ·
Not going to say it isn't, but the more common problem with the injector shields was a hot soak problem. After the vehicle was driven, parked for a bit, and then restarted.
Would cause a fuel starvation problem, like vapor lock. Making hard to start, running poorly until enough cool fuel got through the injectors. Can't say I remember it causing a problem in normal driving.

I'm with Jerry, always start with the basics.
I'm using champs
 

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Discussion Starter · #14 · (Edited)
Not going to say it isn't, but the more common problem with the injector shields was a hot soak problem. After the vehicle was driven, parked for a bit, and then restarted.
Would cause a fuel starvation problem, like vapor lock. Making hard to start, running poorly until enough cool fuel got through the injectors. Can't say I remember it causing a problem in normal driving.

I'm with Jerry, always start with the basics.
I'm using champs 7704 I think. There double plats the dealer sold me
 

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Discussion Starter · #15 ·
Update: took her to a friends shop and scanned it. Well it looked like the voltage didn't change during the misfire to the injectors ( that does not rule out an injector going bad) but it seems like there really dirty according to him, so I'm going to run an injection system flush and see if that helps
 

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I seriously doubt your injectors are dirty, I would bet big $$$ flushing/cleaning the injectors won't help at all.

Champion 7704 plugs are the wrong model, 7034 is the right double-platinum model Champion spark plug for newer distributorless engines like yours.
 

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Discussion Starter · #17 ·
I seriously doubt your injectors are dirty, I would bet big $$$ flushing/cleaning the injectors won't help at all.

Champion 7704 plugs are the wrong model, 7034 is the right double-platinum model Champion spark plug for newer distributorless engines like yours.
I could not remember the number 7034 are what I put in
 

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Discussion Starter · #18 ·
Update: well the idle is still rough. I gapped the plugs again and ran some 44k thou it, and that helped for a little. Still can't seem to pin point the problem. It never stalled out it just seems to me like a misfire. I'm hoping to find the cause soon
 

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I seriously doubt your injectors are dirty, I would bet big $$$ flushing/cleaning the injectors won't help at all.
X2 This guy is a smart cookie ;)

I have yet to see with my own eyes injector cleaner work if its to the point there not spraying right it is time to replace them.
As for your slight miss it could be injector going bad or coil starting to fail. I would lean more toward coil.
Try a different set of plugs. I had an outboard do the same thing and figured out it did not like platinum plugs it ran better with old school no frill spark plugs
 

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Discussion Starter · #20 ·
Update: I ended up putting on a new coil ( I dropped it ) and still idling rough.
I'm still thinking it has to do with the fuel injectors.
 
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