RETZ

New member here posting my first thread. About a month ago at 3,500 miles my 2012 JKU suddenly started idling rough where the engine vibrates to the point when i'm sitting at a stop light and looking through my side view mirror everything is shaking. This only is happening after i have driven for 10 min or so and the engine hs completely warmed up and continues until I shut the ignition down. I'm now up to 4,500 miles and it still persists. I took it to the dealer for a oil change and asked them to check out the idle issue and they said there's nothing they notice and there no code showing up in the computer.
I'm not hearing any ticking sound as i've been reading about. I can't say the engine is running all that well when i'm driving but it's not so obviously bad that i'd want to get into that here because i could be me just over analyzing based on the idle issue and reading about problems others are having with the Pentstar ticking etc. To me there's definitely an problem with the way it idles.
I'm planning on taking it in to the dealer and ask that a sevrvice tech take it for a ride of at least let him sit in the car while it idles but i'd thought I would raise the issue here to see if anyone had an opinon. I know this is a Jeep and it's not supposed to run like a Linclon town car and if i was told the idle was normal i'd say fine but to me it's not right.
Thanks for any advise.

trail_creeper

Does it feel sluggish? Could be a spark plug issue but it's fought to say.

Bosox5

Bring it back to the dealer, and make them go for a ride with you to show the rough idle. It's a brand new jeep, make them fix it.


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RETZ

Yeah at times i'd say it's a bit sluggish when driving. Thanks

RETZ

Yep, that's my plan thanks!

nmeadow

I am having the same problem but my CEL just started coming on too. It's going to the dealership Monday morning.

Teetertotter

When you cold start your engine and try to rev in neutral does it stall at around 3-4 thousand rpms? Mine has been doing this lately, once its warmed up it goes away. Is there a rev-limiter till a sensor detects normal operating psi and temp? Any help would be appreciated.

LIJeeper

Same problem here. Dealer told me its normal for these 3.6s. This is my first Jeep and it has 1850 miles on it. My side view mirrors vibrate a bit and I feel it in the seats. If I have a problem I'm going to be pissed. I had an FJ prior to this and no issues for 75,000 miles. I love the Jeep, don't get me wrong but I will be very disappointed if there is an issue. Please report back on your progress.

RETZ

Sorry I've been away from the forum for a while but here's the follow up to my idle vibration issue. I took it in to another dealer back in September when they kept it for three days. They acknowledged the idle wasn't right but they didn't know what was causing it and said unless there was a error code showing on the computer they couldn't do any work without incurring cost. They told me to wait for a code to show and they can resolve whatever it is or explore more extensively. Very frustrating because it's still happening and seems to be getting worse. I'm up for an oil change so I'm taking it back and making sure they document the issue and ask they look at it again.

sickb4st4rd

My 2012 JK rolled off the line January 2012. It just hit 15000 miles and although I had a mild ticking no other problems noticed so far.

4 weeks ago the engine starts running rough as hell on idling at stop lights. I took it in to the dealer (Larchmont, NY). They admitted they noticed the behavior. They flashed the PCM and sent me on my way. Problem worse and sustained. Very rough idle. As others have said, sounds like a f*******g tractor in a drive through.

Then last week the MIL kicked. All P0306 codes. The light goes off every 3 or 4 engine restarts. I even drove 6 hours at 70mph on a trip with no light on. The other symptom is my highway mileage which used to be 23.6 at 65-70mph with cruise on went to shit. Couldn't get over 19.0 on the highway for the past 2 weeks and now it's back up to around 21.6mph.

Taking it back to the dealer tomorrow will let follow up and let you know what happens.

Thanks


UPDATE:
Dealer had it all day, and confirms it has to be the engine. To be specific, the head and valves will be replaced. He's ordering the parts and when they come in I have to leave the car for a few days. He conceded they've done this procedure on other Pentastars, but not on a Wrangler.

So that is both good news and bad news.

The engine light went out but the rough idle persists.