Shuddering at idle

[Garemlin]

Wanted to see if anyone else had this issue. 2021 Willys 3.6 with no engine mods.

When I start it up cold and I sit at idle I get what I can best describe as a shuddering or surging sound and feel from the engine. It comes on and stops and repeats. I can feel it and hear it. And it's not very subtle. It also happens when warm at idle when I put on the a/c.

Obviously I plan to take it to the dealer to have it checked out. Just checking to see if others have had this issue and what the outcome was.

Edit: Video where you can hear the obvious shuddering. You can even see a little vibration towards the end.

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[atoy74]

Stupid question but could it be bad gas??

 

[Garemlin]

Stupid question but could it be bad gas??

I don't use cheap gas so I wouldn't think so. This has been an ongoing issue for a few months. So the chances of getting consistently bad gas from different stations would be pretty slim.

 

[calipoontappa]

I know what you’re talking about I have the same issue.

 

[Garemlin]

I know what you’re talking about I have the same issue.

So it feels like a rumbling or shuttering at idle on yours?? The sound and feel is almost like it's separate from the regular engine sound and feel? Have you had yours checked out?

 

[calipoontappa]

So it feels like a rumbling or shuttering at idle on yours?? The sound and feel is almost like it's separate from the regular engine sound and feel? Have you had yours checked out?

I’ve had my engine replaced because of a constant ticking noise which they now claim is normal…I have an appointment on Tuesday to take mine in for various issues including this one.

 

[calipoontappa]

https://www.jeepgladiatorforum.com/forum/threads/pentastar-v6-idle.31342/

 

[calipoontappa]

One more
https://www.jeepgladiatorforum.com/forum/threads/rough-idle.41841/

 

[Garemlin]

I’ve had my engine replaced because of a constant ticking noise which they now claim is normal…I have an appointment on Tuesday to take mine in for various issues including this one.

I had the 3.6 in my 2015 Wrangler and 2019 Grand Cherokee. Idle was as smooth as mother's butter. Totally different case here. It's so bad sometimes I can see the vibration in the rear view mirror.

And like I said, and I know it sounds weird, but it's almost as the sound and vibration is totally separate from the regular engine sound and feel.

 

[cb4017]

Any check engine lights?
Don't know if it's the same thing you're talking about but sometimes on the first start of the day mine will stumble for a few seconds before smoothing out. Not a steady miss like from a bad plug or dead cylinder. This usually goes away in less than 5 seconds. Then I won't notice anything the rest of the day. Mine is usually smooth enough that sometimes I have to look at the tach to make sure it's still running. About 6,500 miles on it now.

 

[JTsGarage]

Yes, I've experienced this issue. It seems most noticeable after the ESS system restarts the engine or starting the engine from cold. Sometimes it is more noticeable than others. I've also had two prior experiences with the 3.6 Pentastar - a '13 JKU and an '18 Grand Cherokee - and never experienced anything like this. In my case I'd describe it as only a slightly rough idle. Since it hasn't been accompanied by any warnings or other issues in 18k miles so I haven't bothered mentioning it to the dealer. I personally think the newer Pentastar engines, as they've been tweaked over the years, run better on higher octane gas than regular 87. I still use 87 as the norm, but if I get premium at Costco on occasion the rough idle seems to go away.

 

[arneb04]

Mine only occurs at cold startup until the rpms settle. With a warm engine it is smooth. Not that I want to pick the minivan engine scab but my mother in law has a dodge caravan that does the exact same thing at startup. Always has, and they have like 120k on it now with no issues. I think it’s just something they do.

 

[Cleveland406]

I have the same issue. Happens after sitting overnight, or for more than 4 hours. No check engine lights. My 2015 JKUR and my 2018 Cherokee never had this issue. I've always used top tier gas as well.

 

[Brahmajoe]

Wanted to see if anyone else had this issue. 2021 Willys 3.6 with no engine mods.

When I start it up cold and I sit at idle I get what I can best describe as a shuttering or surging sound and feel from the engine. It comes on and stops and repeats. I can feel it and hear it. And it's not very subtle. It also happens when warm at idle when I put on the a/c.

Obviously I plan to take it to the dealer to have it checked out. Just checking to see if others have had this issue and what the outcome was.

Did you ever find out what this issue is?

 

[ShadowsPapa]

The thing about engine issues like "rough idle" is that it can be caused by any one of a number of things, maybe even more than one. So a solution for one may not be the same as yours.
It may be helpful to know how another was fixed, but I'd not count on it being the same issue.
Have you thought about seeing a dealer about it since it's under warranty?
There won't be any "self-fixes".

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