Pentastar V6 idle

OffRoadMonkey

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My JT runs rough at idle from time to time, dealer says there is nothing they can do since there is no engine trouble codes on the PCM. I had a 2016 JKU with the 3.6 that ran super smooth, I started to feel the rough idle around 1,200 miles now it has 4,000 miles. My brother has a 2018 JLUR and is smoother that my JT. I have tried different fuels and octane rating with no change, did a oil change with no change, I do notice it more when the A/C is ON on MAX. I also feel the steering getting heavy when the idle is rough and turning the wheel while standing still in gear.

I hope that FCA finds something about the matter and issues a TSB that I could bring to the dealer, maybe a PCM reprogram could be the fix.





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RodRecket

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I've noticed a "rough" idle until the engine warms up. I use the term rough very loosely because it is nowhere near feeling like a misfire. Once its up to running temp it is very smooth at idle.

Edit: odo is just under 5k miles
 
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jeepdan

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^^^^ Post above describes mine very accurately. Only 3000 miles on it so far.
 
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Curious to know of the ones that are having a rough idle with no cel. What is your cold and warm idle speed? Could some of the rough idle be to low of an idle speed?

Mine seems to be getting less as it breaks in. I am still under 500 miles and to honest I have not even looked at my idle speed.
 

CookieSoup

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I've noticed a "rough" idle until the engine warms up. I use the term rough very loosely because it is nowhere near feeling like a misfire. Once its up to running temp it is very smooth at idle.

Edit: odo is just under 5k miles
mines the same alittle shacky when cold but once warm its fine. i fee like it should stay at 1,000 RPM for like 90 seconds longer before dropping to what like 600
 

OffRoadMonkey

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I've noticed a "rough" idle until the engine warms up. I use the term rough very loosely because it is nowhere near feeling like a misfire. Once its up to running temp it is very smooth at idle.

Edit: odo is just under 5k miles
Definitely the rough idle is more noticeable on a cold engine, watching the temp gauge closely, as soon as it hits the normal level the roughness goes away like 90% but I do feel it on a Auto start/stop re start for a few seconds and if I am over 30 minutes on idle sometimes it gets as the cold start, it is really noticeable when 4 low is fighting the brakes on a slight incline, but again is hit or miss on mine and I can not find how to replicate it to be able to explain it at the dealership. I will rack up some more miles and monitor if it gets worse. On the flip side my 1998 Jeep XJ has a smoother idle overall and the 4.0L is a tractor engine :LOL::muscle:.
 

Br4hm4

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I was noticing it more and more this weekend. It was rough after I started it...smoothed out, but it seems like pretty much any time the Auto Start/Stop kicks in, after it starts back up the idle is rough and one time felt like the RPM dropped enough to almost stop the engine again.
 

cecaa850

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Possibly running a little rich while in open loop?
 

oldhp3

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2018 RAM 1500 3.6 smooth as silk idle, winter cold or summer heat. Could it be that the 2020's have a EGR valve now and this is the problem? Mine has gotten better, but hunts around for smooth idle.
 

mr_bots

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2018 RAM 1500 3.6 smooth as silk idle, winter cold or summer heat. Could it be that the 2020's have a EGR valve now and this is the problem? Mine has gotten better, but hunts around for smooth idle.
That's a interesting theory. Maybe I'll bust my BlueDriver out and tinker with it to see what variables are floating around when it stutters a bit. Could definitely be a delay between an adjustment of the EGR valve and throttle plate. Hopefully it'll also pick up when it switches valve lift, I'm curious how often it bounces between the sets of lobes.
 

NC_Overland

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Now, I'm starting to notice an intermittent rough idle on mine. It seems to be most prevalent on hot days when I first start it up. It was running horribly on Sunday at the beach after it sat for several hours. It was bad enough that I thought it was going to stall so I put it in neutral and let it rev for like 30 seconds and it was still rough, but idling better. it wasn't till after I drove it for a while that it went back to normal. If it ever runs that badly again, I'm going to have to take it in. I was all the way down at the end of the Offroad Vehicle Beach access at Ft Fisher so that would have been a fantastic spot for a break down. I'm hoping it was just a fluke from sitting out in the salty air on the beach for several hours.
 

cecaa850

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Maybe the flash for the P0300 will help. Can't hurt.
 

JDLouisville

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Once warm, what are y‘all idling at?
my JLs and JKs were around 800 rpm, Gladiator is 500-600
 

TrainMan

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1800 miles, haven't noticed any idling issues.
 

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