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Discussion Starter #1
Hey, I have a fairly new JK 15(2500 miles).My car while accelerating feels good and no issues or when not pressing the gas and letting it cruise. Now while on cruise control or I'm just pressing it down to maintain speed when rpm stays below 2000 it starts feeling like the car is jerking. Its only noticeable highway driving in speeds over 40+. I have 3.21 gears w/ 35 inch tires and recently had an aftermarket dynomax dual axle back exhaust installed. What could be the issue gears, exhaust , or something completely different?
 

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My wife's jeep commander had an issue similar to what u describe and it turned out to be a blown head gasket and misfire in cylinder 1.
Yours is pretty new engine, but you never know.
Eyeball your coolant level in your reservoir see if it's dropping. Like I said probably a long shot but symptoms sound the same.
Good luck.
 

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Hey, I have a fairly new JK 15(2500 miles).My car while accelerating feels good and no issues or when not pressing the gas and letting it cruise. Now while on cruise control or I'm just pressing it down to maintain speed when rpm stays below 2000 it starts feeling like the car is jerking. Its only noticeable highway driving in speeds over 40+. I have 3.21 gears w/ 35 inch tires and recently had an aftermarket dynomax dual axle back exhaust installed. What could be the issue gears, exhaust , or something completely different?
Did you get a flashcal and change the shift points, or change tire speed to correct the speedometer? 35's are a pretty big jump over stock, and I suspect that you went straight for the biggest tires you could get, and didn't reprogram the computer. It needs to Know what tires you put on, so that it can shift correctly.

As a side note, Jeeps are not mere "cars". Jeeps are magical vehicles that can take you anywhere you want to go, and take all of your money doing it. Besides, every time a Jeep is called a car, legend has it, a kitten dies. A cute kitten.
 

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Yeah.... this sounds like a programming thing to me.

I know when I reflashed my Jeep with the "87 octane power tune" from my TrailDash, it started acting a little bit weird climbing up a steep hill by my house. If you press on the gas pedal just the right amount, it tends to "surge". Pressing a little harder or letting off on the gas stops it from happening again. So it's something about just the right amount of throttle under the load of climbing the hill and the way the tune was customized that does it. Doesn't happen if I go back to the stock tune.
 

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As a side note, Jeeps are not mere "cars". Jeeps are magical vehicles that can take you anywhere you want to go, and take all of your money doing it. Besides, every time a Jeep is called a car, legend has it, a kitten dies. A cute kitten.
I was wondering about that, too. He first mentioned that he has a 2015 JK but then he goes on and talks about problems with his car. Was he also having a problem with his Jeep?
 

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Discussion Starter #8
Haha , sorry I was typing so fast. I have reprogrammed my JEEP for the 35 inch tires; on to of that is actually have it set for 34.25 since thats what the measure around. I will try putting it back to stock and Doug he process over and see if it help, thanks.
 

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Not sure if it will help but it worth a shot. Try to calibrate your gas pedal.

1) Insert ignition key and turn to "ON" (not start).
2) Wait for all idiot lights to go out. Check Engine Light may remain on.
3) Slowly depress the accelerator pedal all the way to the floor.
4) Slowly release the accelerator pedal until it's all the way back up.
5) Turn the ignition key to "OFF".
6) Start the engine.
Most drivers notice an immediate change in throttle response, but depending on your driving style, you may need to repeat this procedure periodically due to the computer's adaptive programming. You likely need to repeat this procedure any time the battery is disconnected.
 
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