Engine jerks at low speed...

[Nash_Dj]

Hey mighty Gang,

I would like to pick up your opinions (the more the merrier) on an issue I am having with my ‘25 Rubicon. Some bashing or schooling is welcome too

I bought my new Rubicon after my 2021 Willys blew its engine at 102K km. (In Canada, the warranty is 100K km.). Right after it came out of the dealer, I felt something was not quite right, but I blamed it on the feeling that I might just be sensitive after what happened with the previous Jeep.

Since then, while driving, especially when accelerating from a slow speed, or from full stop, or when lifting foot off the pedal, I get an engine “jerk” feeling. It feels like it skips, pulls, jumps, surges, or hesitates. It hiccups and does not drive smoothly.

When it is cold engine and idling, the idle is also a bit rough, though subtle.

The dealer has seen it back within 2 weeks as I had to check on that, also reported to them that I have excessive gas consumption too (it has been running about 19–22 L/100 km, roughly 1 US gal/mile). They tested it and told me it is “kind of normal,” that the computer needs time to learn my driving style and to allow it about 5K km (3K miles) for that…

I didn’t fully buy that explanation then, and I don’t buy it now. I am at around 25K km at the moment, and the jerking symptoms are high gas consumption is still happening.

I also had my Jeep one more time there for other issues (door latch alignment), and I asked service directly about my engine problem. I believe they checked OBD readings, but I cannot confirm that. I was again told “all is good, nothing to worry about, it is a Jeep”.

For maintenance so far, I have been doing my own oil changes (probably more than needed), at 1K, 5K, 11K, 17K, and 22K km. The last three were 5W30 (the first two were 0W20).

One more observation: when the fuel level is around half or lower, I think the symptoms may get worse (I cannot say for sure).

Based on the description, has anyone experienced something like this, or have ideas what it could be? Anything I can check or try to fix myself? And what should I tell the next service tech (I will even try different service shop).

Thanks very much!

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[bmpcamry09]

Yet another dealer spewing bad information. These don’t “learn” your driving and it’s certainly not going to get better after 3000 miles.

The dealer won’t/can’t fix it. It is tune related and is the variable valve lift system engaging in the engine. I spent a great deal of time diagnosing this and coming up with a fix after I bought my 2025 and noticed the same thing.

Don’t take your Jeep to the dealer any more for the complaint as Jeep has not and likely will not release a fix. This has been covered in multiple threads here and is due to the piss poor way that VVL high lift mode is programmed on this engine. I have several threads on this site and YouTube videos that cover this in depth. Plan on spending about $1600 to fix it for good if you want it gone.

Don’t just take it from me. @alphawolff here is a dealer tech and went down this rabbit hole for years turning tickets in to Jeep engineering and they refused to fix it. Tuning is the only way.

 

[bmpcamry09]

https://www.jlwranglerforums.com/forum/threads/hp-tuners-for-3-6-models-fixing-what-jeep-won’t.163856/

https://www.jlwranglerforums.com/fo...6-jl-3-6-models-bmp-calibrations-tune.164496/

And if you want visual data and explanation, watch this video.



All of this said, nothing is “wrong” with your Jeep, it’s just poorly calibrated. You can drive it as it for years without hurting anything. Although there is speculation and belief that this high lift system contributes to cam wear. But no long term proof of that yet.

Don’t plan on Jeep ever fixing it as the PUG 3.6 is likely to expire after 2027 and they are funneling their engineering resources into new engines for the next gen.

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