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Discussion Starter #1
I'm at just under 85,000 on my 2007 and yesterday I am driving at 65 on the highway and lose a little bit of what power I have and can hear a miss or sputter. The check engine light came on and stayed blinking unless my rpm's went under 1400 for some reason. I used the trouble shooting on this site and figured it down to the spark plugs, wires, or coil. Well, thought I might as well do them all as I would be taking them out and checking everything.

The coil was bad with no current flowing through one of the points so I knew I was replacing that. Went with the NGK Iridium plugs and Carquest premium wires. The coil is the same one that Ford uses so that was easy to find too. Replaced them all today and it's running great. Will update if I see any of the crazy improvements people claim in MPG's and HP. I expect none but just happy with the Jeep running right again.
 

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Discussion Starter #2
And by the way, they say they are 100,000 for a tune-up but the plugs and all else sure didn't look that great when I removed them.
 

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Keep us informed


Sent from my iPhone using Tapatalk
 

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Discussion Starter #4
I plan on doing a tank by tank assessment so I will give numbers as I get them. One thing to check is if your coil is firing properly. To check use rubber insulated or thick leather gloves and a pliers that have rubber handles.
1. Have the vehicle running, just idle, and then remove the spark plug wire at the coil one by one checking for spark.

2. Be careful as you can get one hell of a shock, but the spark should be strong and jump a possible 1 to 2 inch gap, you don't need to seperate it that much.

3. If there is no spark, then you have a bad coil and it needs to be replaced.

Here's a link for the coil and a link for plug wires.

Spark plug wires
http://www.autopartswarehouse.com/search/?Ntt=spark plug wires

Coil
http://www.jeep4x4center.com/ignition-coil-mopar-56032520ae-m.html
 

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Discussion Starter #5
I won't have hard number comparisons till after a couple tanks but I can give a couple updates on how the Jeep runs. Keep in mind that my Jeep had 85,000 miles on the original plugs and they looked every bit the part of needing to be replaced.

I can't really say that I feel any seat of the pants hp, but there is a little more pep to it. This most likely is due to just having clean and new plugs in there. Plus if the coil was going bad it's hard to say how that might have been affecting it.

Now the MPG's. Take this with a grain of salt as I don't have a full tank gone yet so I'm just talking about comparing the instant avg. which I can't fully say is true but at least it's common comparison against itself. My Jeep has 35 inch tires and a 3.5 inch lift. I use the AEV Procal to set tire size(true measure at 34) and gear ratio(4.10) and driving on mostly flat North Dakota land.

In the warm summer temps I would avg about 16-17 and in temps down around the teens and single digits I would drop to about 14-15 or so. I had been down in the 14's before the change and the temps were pretty low single digits. Now the temp today was mid 30's and it was showing 19 MPG or a little over that.

I attribute this to minimal gains and more efficient burning of the fuel by new plugs, wires, and coil. I'm not saying I had the magnificent 4 MPG gain, but it's trending towards some slight improvement. I will continue to update this so that I can get a better overall avg of MPG and feel.
 

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Discussion Starter #6
Ok, through a tank and a half and it is holding steady around 16 to 17 mpg's. Now that's close to what I would normally get in the summertime, but it's been much warmer than normal here.

Bottom line is I believe there is better start up, idling, and slight power and mpg improvement. I won't say it's anything drastic but I attribute it to the engine being more efficient with the new/clean plugs, wires, and coil. The older your stuff is the better the results are going to seem due to the plugs, wires, coil not being as effecient as when they are newer.
 

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I've got 85,000 on my 2008, maybe it's time I replace plugs as well.

I get shit for gas mileage, 13.5/gallon, 35's, 5.38's, full size spare, 3.5" lift, no air dam and to top it off a Gobi roof rack. I'd love to get back to 15 mpg!!
 

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Discussion Starter #8
That's babying it on the road, still drive 65 or so, but definitely lowers it when having fun with the throttle or taking some trails and crap.
 
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