Survey- For those with misfire issues

[Uparms]

With all the Bank 1 O2 sensor codes, all your misfire codes are cascading from it. Given the P0300 and not specific P030X for specific cylinders, it is random misfires across all or multiple cylinders and that leads back to the O2 problem.

Should not be hard for a tech to narrow down. Common issue is a valve cover oil leak dripping on a 02 sensor but wire chaffing may also be involved.

I would not throw the baby out with the bath water over this one.

Great details! Thank you.

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[Uparms]

They ran the software update, minor improvement. Ordered 2 - 02 sensors, arrive in 4 days..

 

[Uparms]

Ran TSB 18-040-24. Installed 2 - 02 sensors. Glad to have it back.

 

[Smart Like Rock]

Had p0300 cel... 2021 mojave..
After replacing all plugs and injectors (had 1 plug and 1 injector go bad)... still couldn't get the cel to clear. Took it to local dealer, compression test shows 185-155-175 on right bank... this on a 70k engine...
Removing the head to see how bad it is....

 

[Tom2020Glad]

Just wow to this thread. What happened to us is why I even went looking for information.....brought me to this.

I just bought my wife her "jeep truck" she has wanted for some time. 2020 Gladiator Overland. 79K miles.

Test drove it probably 15 miles. Fine.

Drove it for probably a couple of hundred miles after taking delivery over 3 days. Fine.

On the way back home on a 450 mile trip, about 150 miles in, the Auto Start/Stop system disables, then shortly thereafter the CEL pops on. It's chugging and surging like mad.

Took it back to the dealer we purchased it from, as we were still nearby. They initially said they thought it was the torque converter or sensors relating to it. Then, when they said it was "fixed" they had replaced the MAP sensor.

It drove fine for about 30 more miles, then it all happened again.

Sounds like what all the others on this thread have experienced. Misfiring, lean conditions. Mimics a dirty MAF sensor......but I don't think these 3.6L setups use MAF sensors. I can't find one.

So.....I find this thread and start reading. I'm freaking out because I can't see that many have had luck with actual resolution......from 2020 until now.

Are there really that many 3.6L Jeeps out there running like this? Why does this particular truck have almost 80K miles on it if the issues were showing up almost immediately after new owners were taking delivery with almost no miles on the clock?

Is there actually any verified reason why these platforms act like this and has any one solution worked over others? I couldn't find anything definitive in my reading half of the 125 pages of this thread.

Thanks in advance.

 

[ShadowsPapa]

Just wow to this thread. What happened to us is why I even went looking for information.....brought me to this.

I just bought my wife her "jeep truck" she has wanted for some time. 2020 Gladiator Overland. 79K miles.

Test drove it probably 15 miles. Fine.

Drove it for probably a couple of hundred miles after taking delivery over 3 days. Fine.

On the way back home on a 450 mile trip, about 150 miles in, the Auto Start/Stop system disables, then shortly thereafter the CEL pops on. It's chugging and surging like mad.

Took it back to the dealer we purchased it from, as we were still nearby. They initially said they thought it was the torque converter or sensors relating to it. Then, when they said it was "fixed" they had replaced the MAP sensor.

It drove fine for about 30 more miles, then it all happened again.

Sounds like what all the others on this thread have experienced. Misfiring, lean conditions. Mimics a dirty MAF sensor......but I don't think these 3.6L setups use MAF sensors. I can't find one.

So.....I find this thread and start reading. I'm freaking out because I can't see that many have had luck with actual resolution......from 2020 until now.

Are there really that many 3.6L Jeeps out there running like this? Why does this particular truck have almost 80K miles on it if the issues were showing up almost immediately after new owners were taking delivery with almost no miles on the clock?

Is there actually any verified reason why these platforms act like this and has any one solution worked over others? I couldn't find anything definitive in my reading half of the 125 pages of this thread.

Thanks in advance.

There are many dozens of reasons for misfires and such things ...looking for one or two causes isn't going to happen. Even 50 years ago there were many possible causes for the same symptoms.
And no....these aren't that bad. You are visiting a hospital to see how healthy humans are.

 

[Maximus Gladius]

Just wow to this thread. What happened to us is why I even went looking for information.....brought me to this.

I just bought my wife her "jeep truck" she has wanted for some time. 2020 Gladiator Overland. 79K miles.

Test drove it probably 15 miles. Fine.

Drove it for probably a couple of hundred miles after taking delivery over 3 days. Fine.

On the way back home on a 450 mile trip, about 150 miles in, the Auto Start/Stop system disables, then shortly thereafter the CEL pops on. It's chugging and surging like mad.

Took it back to the dealer we purchased it from, as we were still nearby. They initially said they thought it was the torque converter or sensors relating to it. Then, when they said it was "fixed" they had replaced the MAP sensor.

It drove fine for about 30 more miles, then it all happened again.

Sounds like what all the others on this thread have experienced. Misfiring, lean conditions. Mimics a dirty MAF sensor......but I don't think these 3.6L setups use MAF sensors. I can't find one.

So.....I find this thread and start reading. I'm freaking out because I can't see that many have had luck with actual resolution......from 2020 until now.

Are there really that many 3.6L Jeeps out there running like this? Why does this particular truck have almost 80K miles on it if the issues were showing up almost immediately after new owners were taking delivery with almost no miles on the clock?

Is there actually any verified reason why these platforms act like this and has any one solution worked over others? I couldn't find anything definitive in my reading half of the 125 pages of this thread.

Thanks in advance.

This is where your own investigation starts. Get a decent diagnostic tool that can diagnose your codes and record misfires. You can only hope it’s an easy fix like changing a bad spark plug, like my last misfire was over 60k kms ago.

 

[Tom2020Glad]

This is where your own investigation starts. Get a decent diagnostic tool that can diagnose your codes and record misfires. You can only hope it’s an easy fix like changing a bad spark plug, like my last misfire was over 60k kms ago.

Understood. I have a diagnostic tool. I see the misfires and lean condition information. I will cross my fingers that it is easy as you state. They (stealership) already changed the MAP sensor and tested a host of other things and haven't found the root cause yet. I also see a lot of folks who have had these issues wiping cam lobes and rocker arms on the passenger side.

 

[ShadowsPapa]

Understood. I have a diagnostic tool. I see the misfires and lean condition information. I will cross my fingers that it is easy as you state. They (stealership) already changed the MAP sensor and tested a host of other things and haven't found the root cause yet. I also see a lot of folks who have had these issues wiping cam lobes and rocker arms on the passenger side.

Biggest mistake jeep person can make is jumping to conclusions or reading too much into such internet posts. Until you have a way to get the codes, including those specific to jeep, and doing troubleshooting, you'll give yourself heartburn thinking about it.

Cam issues happen, but typically with specific sounds, codes, and so on.
Maybe stop reading so many posts LOL

 

[jrekich]

What are typical misfire numbers? I have a few with with no CEL. Below after 1.5 hours towing a camper through western PA from a cold start. Dealer will not touch until CEL.

 

[Hootbro]

What are typical misfire numbers? I have a few with with no CEL. Below after 1.5 hours towing a camper through western PA from a cold start. Dealer will not touch until CEL.

My current 2025 JT, the #3 cylinder shows about 25 or so on a 45 minute commute each way while the other cylinders are in the single digits or teens at most. My 2020 JT was also the same way with the #4 cylinder and my 2022 JT was the #2 cylinder that would show higher than the others.

Pretty much the same thing, unless it posts a MIL, they are not really going to act upon anything. I think most people will always have one cylinder report a bit higher than the rest. Jeep has updated the PCM software a few time to account for these types of spreads. Thing to keep in mind is that the algorithm they use to record misfires is somewhat of a guess based on knock and few other parameters and not all misfires recorded would be a actual misfire.
Went down the rabbit hole with my 2020.

Given the type and length of driving you were doing, I would call that "normal" on the sliding scales of things with this engine.

This was from my 2020 JT:

 

[jrekich]

Thanks! …and a rabbit hole indeed.

 

[Tom2020Glad]

Ran TSB 18-040-24. Installed 2 - 02 sensors. Glad to have it back.

Hey Uparms - how's your truck been since they installed the 02's?

I just got a call from the newest service tech working on my truck, he says that oil is leaking from the passenger side valve cover area and contaminating the O2.

I can't recall from all of the stuff I have read if that is actually an issue with all of the misfiring and such, but I know it can certainly be a cause of it.

$700 for the gasket replacement and $450 for the O2 replacement. LMAO I'd do it all for $250.

 

[Uparms]

Hey Uparms - how's your truck been since they installed the 02's?

I just got a call from the newest service tech working on my truck, he says that oil is leaking from the passenger side valve cover area and contaminating the O2.

I can't recall from all of the stuff I have read if that is actually an issue with all of the misfiring and such, but I know it can certainly be a cause of it.

$700 for the gasket replacement and $450 for the O2 replacement. LMAO I'd do it all for $250.

Its been great till 31k. CEL P0300.2 weeks ago, pulled into dealer day it happened, they scanned. Jeep At dealer now. Cel went out but I never cleared the code so they could see it yesterday for service. They are trying to replicate miss fire but I doubt they can?? Drove great w CEL and after CEL went out.
Good luck!!!

 

[ShadowsPapa]

What are typical misfire numbers? I have a few with with no CEL. Below after 1.5 hours towing a camper through western PA from a cold start. Dealer will not touch until CEL.

My 2022 would typically run single digits to none, depending.......
We also had a Grand Cherokee that AlfaOBD correctly diagnosed with ignition misfire but no MIL set. I took the jeep and my printed report to dealer who found a TSB for spark plugs that met our symptoms. Sometimes things can be narrowed down with other diagnostic methods. But I'd not sweat your situation at this point. Perfect combustion is hard to achieve especially at highway speeds and loads.

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