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Rough idle...Normal?

28K views 19 replies 14 participants last post by  Baja-D 
#1 ·
New Compass with 2.4L with 2100 miles. Has a rough idle and feels like it wants to stall. Can be in or out of gear and more present when warmed up. Truck shakes when stopped but takes off OK. Engine sounds a bit rattlely when in park and listening from the front. I will take it in soon to the dealer but wondering normal or ?

Thanks for any feedback,
Baja-D
 
#2 ·
Hi Baja-D,
We are sorry to hear about your recent concern. If you would like additional assistance with your dealer from our end, please private message us!
Laura
Jeep Social Care Specialist
 
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#3 ·
"Rough idle" is a bit subjective without like a video or something, I'd say these 2.4 engines have a very rough idle but that doesn't mean we are talking about and experiencing the same thing. The engine certainly lacks refinement, balance, and isolation in my opinion but that still doesn't mean whatever you have is normal. Engine and transmission mounts need to be checked, if those are OK then its probably fine because the car would know and throw a check engine light if it was misfiring or anything like that. It might chalk up to something like "this is what happens when the computer tunes it to the absolute bare minimum amount of fuel and revs to keep the engine alive". Or in other words, rough idle maybe = less fuel used when idling. Don't know for sure, just guessing.

When mine is idling it will cause the steering wheel to quiver and the zippers on my backback in the passenger seat will wiggle and chatter, the passenger headrest will be visibly shaking... pretty strange considering all the effort they put into nonsense like an insulated double-wall oil pan but I'm at 34k miles of this now and its still driving just fine.

Its a little bit smoother than my other car I sometimes drive to work, which has a carbureted three cylinder motor. You want to talk about rough idle, that three cylinder from the 80s takes the cake for sure! Alas these 2.4 motors are super el cheapo mass produced things. You probably notice the roughness especially if your previous car was a Honda, now they have some smooth, well-isolated engines in their cars...
 
#5 ·
Wow that is interesting. Mine is super smooth, so much that when I stop at a traffic light I sometimes need to check if start/stop turned the engine off. I cant really feel if the engine is running or not if there is enough background noise to block the engine noise. But maybe it is specific to some cars car/engines since in my case start stop also turns the engine on/off without any shaking, which is something a lot of people complain about. I agree that since it is a greatly mass produced engine that is also fairly complex, there likely is some variation among units.
 
#7 ·
Ours is the same way. Not even 1000 miles on it, but it seems pretty rough, especially with a cold start. To me a rough idle is a little shaky, moves up and down a bit when it should be even... I was ever-so-slightly concerned about it, but not so much now that I saw these posts.
 
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#8 ·
I have a 2016 with74000 miles that had a rough idle. Before the throttle body went out. Replaced it was good for a day or two then rough idle and miss came back. So I decide to look at owners manual and found that plugs are due @60000 miles and no @100000 like all other vehicles. I quickly found out why, in the infinite wisdom of Fiat Chrysler they put regular ngk plugs instead of platinum plugs like most other manufactures. Most regular plugs are usually only good for about 30000 miles. I put autolite platinum plugs now you can set a full glass of water on the engine with out spilling a drop. So I would recommend that you check the plugs no matter your mileage that could be your problem.
 
#9 ·
Johnjones23072 said:
So I decide to look at owners manual and found that plugs are due @60000 miles and no @100000 like all other vehicles. I quickly found out why, in the infinite wisdom of Fiat Chrysler they put regular ngk plugs instead of platinum plugs like most other manufactures.
I love to bash Fiat where bashing is due, but its worth mentioning that the 2nd gen (2017.5+) with the 2.4 are now coming with "dual precious-metal spark plugs" and the book says they get replaced at 100,000 miles, so it would seem they have remedied this deficiency and it is not contributing to why our 2nd gen 2.4s have a rough idle.
 
#15 ·
Cobrafixer said:
almost sounds like a solid lifter cam when cold!
Might be just the way the Multi-air system is tuned for cold start. Isn't it sweet how much aggressive growl the stock exhaust has on cold start though? (and then totally goes away once warm...) My exhaust barks loud enough on cold start to mostly cover up the sound of the lifters grin:
 
#16 ·
Today I've finally solved my rough idle issue that I had for 55 freaking years with a transfer pump and a ******* cigar. No dealers, about 10 mechanic shops and 2 tuners didn't solve it.
I did the smoke test and it was leaking by the oil cap. I've solved my problem with a $5 dollars cap and a 99 cents cigar that I smoked in the end 💪.
(2014 Jeep Compass 2.0)
 
#19 ·
I also face same with 1.4 MultiAir2 engine, during city drive once stopped in red lights. It could easily be felt as strokes to your foot holding the brake pedal. Vibration in fuselage is in small amounts at the moment with 4500 KM total driven distance, but you can still feel it. It is obvious that it is related with engine air intake system.
I guess it is the tolerances in the air intake manifold pressure and temperature sensors. Maybe a future software will solve this issue.
 
#20 ·
Took truck to the dealer and had them check it out....nothing abnormal found. The rough idle is more of a vibration than any kind of miss. It does not affect takeoff and the RPM's stay steady. Just this shaking that is quite noticeable. Comes and goes, does it in and out of gear but only at stopped idle. Wonder if this is another gas saving feature?!
 
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