3.6L "Hiccup"

[DaltonGang]

It's A Jeep Thing.

Sponsored

 

[MichaelAnthony]

I have an auto and it has been doing it since day 1. I always called it a burp and at first I thought it was cool and no big deal, however when I am out wheeling it is very annoying when trying to negotiate rocks or hills or a mudhole. not sure what the cause is or why.

 

[JeepCares]

Hey All,

First off, I love this Jeep! I'm coming from a 2019 Camaro ZL1 1LE and I thought I was going to miss the power and handling but I don't -- I'm too busy enjoying the high driving view, utilitarian feel, and infinite customization -- it just feels more me.

I'm experiencing two things that may be unrelated.

#1. Hesitation / "Hiccup" often while maintaining speed or light acceleration around 3rd gear & 3k. It feels like a 1/4 second cut in power. It's not super jarring, if you were not driving you'd just think we drove over a tiny bump in the road but you can feel it. It is pretty random, not just when the engine is cold -- it happens when cold and at full operating temp.

#2. Slightly rougher than expected idle? This may just be a characteristic of the engine that I need to get used to but it feels to me like the entire car vibrates a mild-but-noticeable amount when idling. Idle appears to be about 700rpm give or take.

I have about 1200 miles on the clock, 100% stock and thoughtful brake-in.
It's a manual transmission, no real load, just me and my wife and daughter.
I live in California and the weather has been clear and mid-50s.
I've been putting 91 octane in it only because I'm still at low mileage, i'll probably switch to 87 soon.

I'd appreciate any insight from you experienced Pentastar 3.6L owners.

Thanks for your help!

Yes - I notice the same 1/4 second "skip", at around 3k RPM. I will try to take a video as well. I think you hear it with the engine more than feel it. It may have to do with the e-torque as I believe it does help to slow the engine down for shifts, but the engine is not shifting during this time, could be a "bug".

I'm running 87 and see no issues with performance or rough idle.

My 3.6 (auto) vibrates at idle, I usually run mobil 87 gas, sometimes shell. It's been doing that since the day I brought it home. I did notice mine idles a little bit smoother in neutral.

It's a strong enough vibration that if I'm carrying cups of soda with ice in them, the ice will rattle in the cup lol. If nobody's sitting in the passenger seat I can see it jiggle.

I figured it might be motor mounts or something but I've had the hood up with the engine running before and haven't really seen anything that'd indicate a problem. Meh. Will get it checked out once things get healthier outside lol. Maybe our motors were made on a Friday.

6speed here, mine does the same hiccup. did it since it was new. did the clutch recall unfortunately the dealer said it passed the "stall test" even though i asked them to drive the damn thing and feel it slipping. The clutch sucks in this thing. Dealer says nothing wrong with it. IM eventually going to get tired of it put a centerforce or something stronger and better in it. i have almost 40k on mine btw.

I have an auto and it has been doing it since day 1. I always called it a burp and at first I thought it was cool and no big deal, however when I am out wheeling it is very annoying when trying to negotiate rocks or hills or a mudhole. not sure what the cause is or why.

Good morning everyone,

I heard your concerns and sincerely apologize for any inconvenience this has caused you thus far. The best course of action would be to schedule an appointment with a nearby Jeep dealer to get your concerns properly diagnosed. If you'd like additional support while your vehicle is being serviced, please don't hesitate to reach out to our JeepCares team via private messaging with any questions or concerns. Thanks-- have an awesome day!

Courtney
Jeep Cares

 

[Monkeynono]

I have a 6 speed 12 k miles and have the same mis or stumble. Happens around 2500-3000 rpms. It is not clutch related. Without looking at data I want to say it is a lean issue or to aggressive or sudden change from the VVTI.

 

[HeavyUser]

I get the same burp feeling, don't really think anything of it, also if I were to compare my jeeps idle with an audi then I would say it idles rough. In reality I think all this if just the unrefined characteristics of the jeep.

 

[Oneil2186]

My 2018 6 Spd does the hiccup/misfire in 3rd on light accel as well. Did a ride along with a service advisor to demonstrate and he agreed that is was there but no fix as the PCM was current. With 6 months left on the warranty my hope is Jeep can come up with updated tune for the PCM. Its a bit annoying to have to go the aftermarket on a stock vehicle to fix something the engineers and dealers from the OEM know about and deny.

 

[Truckn]

Quick update -- My gut has been telling me that this "hiccup" issue is related to traction control, so I did an experiment and have been turning traction control off (along with my ritual of turning off auto start/stop).

It's been over a week and it seemed to have gone away... Until today, I felt it.
I still believe that it is traction control related. When you turn the traction control off, its not TOTALLY off. So I'm going to try plugging in a Tazer Mini JL and do the FULL TC OFF and see what happens.

While leaving TC on (default) -- I was feeling the hiccup almost daily.

While turning TC semi-off -- I only felt it once in the last week.

With TC FULL OFF -- if it doesn't appear for a few weeks, I will then feel pretty confident it is a TC issue, probably flaky wheel or something like that. We'll see.

 

[multicam]

Hey, OP- please get back to us on your little experiment; I’m really looking forward to what you find out.

I have the 6 speed too and just noticed this. I have about 25,000 miles on mine and never experienced this until the last couple hundred miles. The only thing I’ve done recently to strain the jeep was rescue a Rogue out of a ditch when it snowed a few weeks ago, which made me think maybe I put too much stress on the clutch... but your traction control theory is interesting too because it has been raining a lot lately here. I’ll pay more attention tomorrow.

 

[neil]

2020 nearly stock, I notice the same thing, it's right below 3K for me. I think engine or TC. oil pump also kicks in around there.

 

[GeeGuid]

I’m not feeling the “hiccup” but definitely feel a rough idle. ‘21 JLUR 6-speed, 2500 miles. Oh yeah, I don’t feel much accelerated in 3rd...almost flat.

 

[Truckn]

I have a 6 speed 12 k miles and have the same mis or stumble. Happens around 2500-3000 rpms. It is not clutch related. Without looking at data I want to say it is a lean issue or to aggressive or sudden change from the VVTI.

I just googled it -- apparently I can use my HP Tuners OBD2 data logger on this Jeep! If the TC experiment fails, I'll spend some time datalogging to see if I can trigger the hiccup and capture timing or knock retard, maybe even AFR if the computer has it.

Hey, OP- please get back to us on your little experiment; I’m really looking forward to what you find out.

I have the 6 speed too and just noticed this. I have about 25,000 miles on mine and never experienced this until the last couple hundred miles. The only thing I’ve done recently to strain the jeep was rescue a Rogue out of a ditch when it snowed a few weeks ago, which made me think maybe I put too much stress on the clutch... but your traction control theory is interesting too because it has been raining a lot lately here. I’ll pay more attention tomorrow.

Will do! Don't worry about your rescue op -- I think enough of us here have the issue that it's probably just something common and not caused by the strain. Rescues are in the Jeep's DNA!

 

[zrickety]

Thanks everyone for the input. I will check with the dealer, you never know but in my experience they won't help you unless you can reproduce the issue consistently or it's just broken.

Fuse box check is a good tip, thank you!

I found this thread, sounds similar to me:
http://www.ausjeepoffroad.com/forum/showthread.php?t=151736

So far it hasn't been a serious issue, just an annoyance, I'm okay with waiting to see if it gets worse or goes away. I was just hoping to hear from one of you saying "This happened to me and here's how you fix it"

Thanks all!

I was going to say, this is a pretty well documented issue. My 2020 has this intermittent hesitation also. I wouldn't think anything of it unless it gets worse. Something with factory ECU tune I suspect.

 

[Truckn]

I was going to say, this is a pretty well documented issue. My 2020 has this intermittent hesitation also. I wouldn't think anything of it unless it gets worse. Something with factory ECU tune I suspect.

I tried searching and found nothing. Can you share a link to some of the similar cases?

EDIT: I tried searching through the TSBs and this was the closest thing I could find:
http://www.wkjeeps.com/TSB/tsb_wk_1800409a.pdf

It sounds very similar but its for a 2009.

If the problem is software then there is no chance of us getting it fixed. Dealerships play dumb and give you the runaround until they get some instruction from the manufacturer.

 

[DanW]

Lots of good suggestions here. I agree that it needs to be looked at. For reference, I've also got the 6 speed. I've not felt any hesitation like that and the idle is so smooth, that with music on to where I can't hear the engine, I've gotten out of the Jeep thinking that it was off. So the idle should be very smooth. (Of course, old age hs a ittle to do with forgetting the engine is off. I'm also still not used to not having a key, and never will be, since I still have my JK.)

Remember, too, that noise and vibration can be VERY subjective. Some are more sensitive to certain frequencies or subtleties of it than others.

Has it always done it or did it develop after you put a few hundred miles on it?

Side note: I do know that @Elsinore73 gives a great example. I feel absolutely no difference between 87 and 93. But my friend who helped design the Pentastar said that the test equipment shows with absolute certainty that there is a difference in smoothness in the Pentastar between lower and higher octane. The test equipment showed it clearly in development. But most can't feel it. He did offer a quite detailed and interesting engineering explanation as to why. I don't understand it enough to be able to explain it, but it made perfect sense. So my friend runs 93 in his Chrysler 300. I don't. I don't feel the benefit at all. But you might try it just to see what happens.

If someone with a 6 speed who doesn't feel these things lives close to you, meet up and have them drive yours and you drive theirs. That'll confirm it and help you to explain to the dealer or tech what is going on.

But it does not sound normal, to me.

Another thing I'd suggest, if you don't do it already, is to run Top Tier gas. That means a big brand, like Shell, Exon, Mobil, Chevron, Phillips 66, and others. You can google it and find the list. But i think that's important, too.

One other thing my engineer friend said. Run this engine hard. Give it an Italian tune-up once in awhile. It is good for it. It might even help smooth things out. Get it to the upper rpm range when you can. It cleans things up, gets fresh oil to certain areas in the complex valve train, and its fun with that 6 speed! It is fine if you don't and will last a long time, but it is better if you do. Again, that's straight from one of the Pentastar's parents!

Let us know how it turns out!

 

[DanW]

I saw OP's update after I posted. I'd suggest riding in an older 2018 or 2019. Maybe sometimes the most recent firmware in the PCM isn't as good as an older version?
Who knows, but It is interesting that the TC may be involved. Can the TC be 100% disabled? Maybe a Tazer can do that?

Maybe just reflashing or replacing the PCM might make a difference, even if the current one shows no issues. If I were the dealer service tech, Id consider that.

Sponsored