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3.6 L Engine Misfiring ? Rough Idle

astrogirl333

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I just got 2021 JLU on Dec 9 with 45 miles on it. Now Dec 27 I have about 2400. A few days ago i noticed when idle, the engine felt really jumpy and rough and would get a little better when I drove it and RPM around 3000. Then yesterday I was accelerating and it like wouldn’t go faster (?), felt like the gear was stuck and just couldn’t go and then i pushed more on the gas and my check engine light started flashing but then stopped. Has been on solid ever since then. But it’s just really rough and jumpy feeling and based on other threads i’ve read, people have had similar problems so i’m hoping they can fix it no problem. Idk exactly if it is the engine misfiring but I just dropped it off at jeep tonight for them to see it tomorrow. I need to drive my jeep 2000 miles to montana in about a week, so, i really need everything to be okay. I just traded my old 2016 JKU with 3.6 L (that never had any problems until cam shaft went bad and i replaced it but then traded it in) with 146k miles on it for this new one.
Just kind of disappointing spending 45k on a car and something is wrong already :/. Makes me nervous to drive it across the country especially if i’m gonna be in the middle of nowhere i don’t want my brand new engine to fail me.

EDIT: I have also noticed that my oil temp runs a little low (?). the gauge has never reached the halfway mark ever since i got it which i wondering if that was normal. It’s always around 188-190° which i feel like it should be around 240°. wonder if this is related to engine misfiring :/.

Jeep Wrangler JL 3.6 L Engine Misfiring ? Rough Idle 22061F57-70FD-4CFD-95D3-EE4B38133301
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mwilk012

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It probably has a valve cover leak that is dripping on an O2 sensor. My JLUR did this. It was a quick fix under warranty.
You have zero reason to believe that this is the same problem.

The dealership will get it worked out. The 3.6 has been around a long time, it’s common failures are simple to fix. You’ll be back on the road in no time.

Modern vehicles have thousands of components that all have to work exactly right to keep things running smoothly. It’s a wonder of science that any of them ever stay running.
 

HeavyUser

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You have zero reason to believe that this is the same problem.
Actually he may be right, I had the same exact issue as the OP and the fix was exactly what Wibornz stated. My O2 sensor was fouled out which was causing misfires and a flashing CEL.

What made you think he had 0 reason to think his issue and the OPs could be related?

@OP, your oil temp is normal.
 
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astrogirl333

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update: Only was at jeep for a day and they had to replace all my spark plugs. they said this is a common problem for these new wranglers (recall??), it’s made from silicon and it cracked and they have new updated spark plugs so, beware i guess. although i only think one of mine cracked but the replaced all of them.
drives great, good as new. little annoying though, but i understand there’s so many components something is always bound to go wrong. but easy fix
 

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mwilk012

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update: Only was at jeep for a day and they had to replace all my spark plugs. they said this is a common problem for these new wranglers (recall??), it’s made from silicon and it cracked and they have new updated spark plugs so, beware i guess. although i only think one of mine cracked but the replaced all of them.
drives great, good as new. little annoying though, but i understand there’s so many components something is always bound to go wrong. but easy fix
You’ll probably be back.
 

mwilk012

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Actually he may be right, I had the same exact issue as the OP and the fix was exactly what Wibornz stated. My O2 sensor was fouled out which was causing misfires and a flashing CEL.

What made you think he had 0 reason to think his issue and the OPs could be related?

@OP, your oil temp is normal.
No evidence at all to lead to that conclusion besides “misfire” which is nonsense.
 

wibornz

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No evidence at all to lead to that conclusion besides “misfire” which is nonsense.

Well I experienced that exact problem. Going down the road, got misfires. Took it in and there was a small leak from the valve cover gasket that was leaking directly on to the O2 sensor causing the JLUR to misfire. They replaced the gasket and the O2 sensor. Then all was fine again in my JLUR world. So maybe it is nonsense in your world, but not in my world.

Thanks for diagnosing my problem as nonsense from approximately 984 miles away without looking at my JLUR. Once again bam the power of the internet.....
 

mwilk012

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Well I experienced that exact problem. Going down the road, got misfires. Took it in and there was a small leak from the valve cover gasket that was leaking directly on to the O2 sensor causing the JLUR to misfire. They replaced the gasket and the O2 sensor. Then all was fine again in my JLUR world. So maybe it is nonsense in your world, but not in my world.

Thanks for diagnosing my problem as nonsense from approximately 984 miles away without looking at my JLUR. Once again bam the power of the internet.....
Nowhere did I say your problem was nonsense. Diagnosing someone else’s vehicle over the internet with 0 evidence is, so, way to make my point for me. You’d be just as accurate if you came in here and said he had a bad camshaft.
 

IVIystic

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FWIW - Came here to report that I had the same issue at 46k. Valve cover leak and oil dripping on to O2 sensor. Still covered under powertrain warranty. Technician wrote up the job at 19 labor hours, so won't be an "overnight fix" if this happens to you.
 

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Actually he may be right, I had the same exact issue as the OP and the fix was exactly what Wibornz stated. My O2 sensor was fouled out which was causing misfires and a flashing CEL.

What made you think he had 0 reason to think his issue and the OPs could be related?

@OP, your oil temp is normal.
Is there anyway to diagnose if this is the issue?
 

mwilk012

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Is there anyway to diagnose if this is the issue?
It is pretty straightforward, yes. Misfire faults on cyl 1,3,5, maybe o2 B1S1 circuit faults, pop the hood, look at the rear right of the engine. Every fault is diagnosed the same way. First identify what is actually happening, then why, then fix it.
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