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Discussion Starter · #1 ·
I have noticed this oddity about a half dozen times the last few months. I have a 2014 JK 2dr Rubicon X Stick-Shift with about 5k miles and when I go to stop completely, the engine revs up for a few seconds before the rpms go idle. The first few times this happened my A.C. was on full blast so I attributed it to a power consumption thing and never really paid much attention but the last few times this has happened (the most recent last week) it definitely got me a little concerned.

Basically, on most occasions if I come to a complete stop the RPM's steadily go down before going idle and everything is smooth as it should be. So if I'm approaching a red light I depress the clutch put the stick in Neutral and depress the brake as normal. When this oddity occurs and i'm coming to a complete stop the RPM's will drop normally but once I'm close to a full stop or even fully stopped the RPM's REV UP. When this happens the RPM's go from nearly nothing at idle to about 500-1k rpms. Nothing extreme, but you still feel it pretty good. After 2-3 seconds the RPM's just drop back down to idle and everything is smooth.

Anyone else experience this with their stick JK's or have any idea what may be causing this? :confused:
 

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Discussion Starter · #4 ·
Hmmmm. I may need to setup a service appt if this continues to happen. . Anyone have any ideas what may possibly be causing this anomaly?
 

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AC compressor kicking in and out?? Not sure as I don't have AC on mine... but it is common to happen on other vehicles
 

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Discussion Starter · #6 ·
@marslim... I thought the same thing initially but the last couple of times its happened the A. C. was completely off. Anyone have any other ideas?
 

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AC off but was the defroster on? Defroster on also runs the compressor. My 6speed does not do this. However, the idle in the pentastar is low, usually around 500 RPM. Maybe something is causing a dip in RPM at idle and the computer is compensating to prevent a stall. Take it to the dealer if it continues.
 

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I know you've said you don't have AC on but I'll offer this in case you didn't know. AC is automatically on when the air diverter is on defrost or even bi-level whether AC is selected or not.

Oops JKwrangler beat me to it.
 

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Discussion Starter · #9 ·
Thanks for the responses I appreciate it. . I will pay attention the next time it happens but I'm nearly positive the A. C. Defrost etc was completely off the last couple of times. A buddy told me the same thing regarding the computer compensating to prevent a stall. . The thing that's odd is I'm in neutral And with the clutch depressed so the Wrangler should never come close to stalling In neutral and with the clutch In. . And Noone here with or without A. C. has ever experienced this either which concerns me. If it does it again I'll set a service appt.
 

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Let us know what you find, I'm kind of curious now. Definitely sounds like something puts a heavy load on the engine (like the compressor) causing the computer to compensate by raising rpm... But it could be some electrical issue too. Who knows now with all the electronics...
 

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At what point are you shifting into neutral or disengaging the clutch?

If you coast/brake down to low speeds with the transmission in gear and clutch engaged, the computer will add throttle trying to prevent stalling if RPMs drop too low. If you then disengage the clutch, RPMs will shoot up a bit because of the extra computer-controlled throttle, then the computer will react to the suddenly reduced load, reduce throttle, and resume normal idling.

I've had this happen if I stayed in gear down to below 1000 rpm while coming to a stop.
 

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Discussion Starter · #12 ·
When this has occurred I had the clutch engaged fully AND the Wrangler in neutral. As I started to come to a complete stop I could feel the vibration in my foot on the clutch when the engine revved. The last few times thus occurred I have been very aware as it occurred a few times prior. So again while coming to a complete stop with the gear in neutral AND my foot depressing the clutch fully the engine Revvs a few hundred rpms for a couple of seconds and then idles.
 

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Discussion Starter · #13 ·
Let me also clarify that usually I'm engaging the clutch and shifting to neutral at around 3000rpms. When the issue occurred last week I was going about 40-45 and right around 2500-3000 rpms when I was abruptly cut off by an idiot who obviously wanted to get into the left lane to turn and realized at the last second. When I was cut off I slammed the clutch shifted to neutral and hit the brake hard. Everything was fine until I nearly came to a complete stop and the Wrangler revved a few hundred rpms and idled. In the times prior to engaging the clutch and shifting to neutral I was at around 2000-2500 rpms and 20-30mph when I start to brake everything is fine it's only right before idle the engine Revvs a few hundred Rpm then in 2-3 Seconds idles smoothly as normal.
 

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It's just the computer thinking you're gonna stall the engine and it revs itself up to make sure it stays running. Make sure the clutch is all the way in. Might need it adjusted. Maybe the fan or alternator kicked in and the engine revs up a little for the extra load. It's not uncommon.
 

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Discussion Starter · #15 ·
Blazenblu thanks for the info. When you say this is not uncommon are you referring to this happening to you with a manual or people you know? Have you read about this here at the forums? . When you say it may need to be adjusted what are you referring to that may need to be adjusted?
 

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I'm not trying to say that you're driving the jeep incorrectly, just a tip. The clutch pedal should only be engaged temporarily. I.e to begin moving or switching a gear. Don't keep the pedal depressed, say, waiting for a traffic light or at a drive through. If the gear box is in neutral, there's no need to hold the pedal in. Hope this helps and I'm not coming across as an ass hole lol
 

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Blazenblu thanks for the info. When you say this is not uncommon are you referring to this happening to you with a manual or people you know? Have you read about this here at the forums? . When you say it may need to be adjusted what are you referring to that may need to be adjusted?
It's not uncommon for any manual. My Mazda RX -8 did it too. You just get a little rpm spike every now and then waiting at a light or whatever. If the rpms dip below a certain point (like letting the clutch come up slightly without giving it any gas) the computer just gives it a little gas.
 

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Discussion Starter · #18 ·
That's good to know. My only concern is when it's happened the last couple of times I was in neutral and my foot want anywhere near the clutch as I was braking to a complete stop. Having my foot on the brake slowing from around 35-idle. Once stopped completely the engine revved a few hundred rpm before idling. It's good to know this isn't completely uncommon but Noone else with a jk has chimed in saying this has occurred with them which concerns me.
 
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