Survey- For those with misfire issues

[Idlethunder]

As strange as this sounds, the misfire count on my 22 JTR has come way down the past few weeks. I monitor them almost every drive with Jscan and the last time I had more than 100, which was the average, came on a 60 mile trip back in mid November. Since then, they have gone down to averaging 20 to 30 on any 30 mile drive. The only thing that has changed has been the switch of the local stations to winter blend fuel. Looking back my first cel came in early May which would have been about the time we changed to summer gas. To me this does not make sense, if there was any change at all, they would get worse with winter fuel not better. It may be nothing more than just coincidence. I am at almost 10,500 miles now and when I spoke to my service local service department last week, they told me that the only new recommendation from Stellantis was to recheck all electrical connections and that has been done twice. I am still leaning toward this being a software issue because it happens across all cylinders, yet I can’t hear or feel any misfires and most of mine happen within the first few miles after a cold start. Does seasonal fuel make sense to anyone or am I just reaching?

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[ShadowsPapa]

Anything is possible but personally I doubt the fuel.
Did u c any of my weird misfire posts? It ended up being an issue with CCDIFF learning. They forced a learn and so far.............so good. It was 1 bank only (even bank) and it was fine after a few minutes. 6,000 miles and it hadn't yet learned cam/crank relationship. There is actually a tsb on it but i can't get my hands on it yet.

 

[Idlethunder]

Anything is possible but personally I doubt the fuel.
Did u c any of my weird misfire posts? It ended up being an issue with CCDIFF learning. They forced a learn and so far.............so good. It was 1 bank only (even bank) and it was fine after a few minutes. 6,000 miles and it hadn't yet learned cam/crank relationship. There is actually a tsb on it but i can't get my hands on it yet.

I’ve been keeping up with the misfire threads but because most of mine were from a cold start, I didn't think my problem was very similar to the one you were having but that changed today. I had driven 30 miles so the engine was up to temp and stopped for lunch. Came out of the diner 30 minutes later and immediately got the readings in the attached screen shots. This is very similar to what your Overland was doing, correct?

 

[ShadowsPapa]

Check JSCAN for CCDIFF and similar, like cam crank, etc.

 

[Idlethunder]

Check JSCAN for CCDIFF and similar, like cam crank, etc.

Driving her car to OKC tomorrow to do some Christmas shopping but I'll put some miles on the Gladiator and check those in Jscan on Sunday. When you are able to find a copy of the tsb that will definitely be helpful but surely my dealership can find it. I'll report back what I find Sunday evening. Thank you for all your help!

 

[ShadowsPapa]

It's not uncommon to see some misfires when cold. It's really hard to deal with a cold combustion chamber, cold fuel and the fact that O2 sensors are not yet warmed up and reporting in. It's got to go by a best guess table, to put is in basic, simple terms. Until it gets sensor information and things are warmed up, a few things won't be perfect. Idle even to this day on a cold engine requires a richer mix.

I got a few when it was cold - very low single digits if it did happen - all normal, so they were ignored.

Mine developed a pattern - and that's what you want to look for cold or hot or warm.
Patterns - I guess that's where the psychiatrist says I excel - pattern recognition and puzzle solving. It's helped me in life - but just can't be explained or learned.

Anyway, mine did the very few on the odd side - the passenger/right side, but there was a definite pattern. It was the left side every time, and it only happened after it was thoroughly warmed up and stopped for 20-30-45 minutes (20 was the shortest, 45 was the longest), then restarted again.
This is one reason I like the "boxes" on jscan - if you choose certain things in the right order, the pattern is very obvious.
2, 4, 6 - driver side cylinders.

 

[Lunentucker]

I wish I knew with certainty what fixed the single cylinder misfire I was having.
The tech swapped coil packs with the adjacent cylinder to see if the issue followed the coil pack, and it disappeared completely and hasn't been back.
The problem is that's also when they did the Z37 flash, so that further clouds the science.
Was it just a poorly seated coil pack? Did the PCM flash lower thresholds or change some timing or firing parameters? Combination?

Whatever it was in grateful and glad to not have that to worry about.

 

[Gobi22]

If you have had the CEL light come on with misfire codes, please respond to this thread.
Build date: (see picture below) can be found on drivers door well. MDH=month/day/hour (24 hour format)
Mileage when it first occurred:
How many times has it occurred:
What exact codes did it throw:
Is the issue on going? Y/N
If so, what has been done to try to solve the issue?
Was the issue ever fully resolved? Y/N
Rules for posting in this thread:
Keep it to on topic post & discussion only!
lets keep topics to solutions & factual information, not complaining & guesses.
Don't post multiple post with same info. Instead edit your original post with the correct info.


I'm just curious how many of us are dealing with the same issue and how much of a problem it truly is. I know for a fact that on my build date that 10 other JT's failed final inspection for the same misfire issue so I know there are plenty out there based off of this alone.

I have a 2022 JTR that I bought in 0ctober 2022 it only had 396 miles on it when it had a check engine light. I have a Blue Driver device to check codes and a P0300 and a P00FD codes came up in the report. I was not able to clear the P0300 code. I was using my Jeep for for Christmas shopping visiting many different places, when we were leaving the last store the check engine light came on while still in the parking lot. I never experienced any running problems. It happened on a Sunday and I called the dealership on Monday and took it in on Wednesday. I was able to pick it up on Friday and they told me there was a TSB for my Jeep and they did an update on the computer and told me if it happens again they will have to replace the computer. I have not been able to run my Jeep this week to test it until today and so far everything is fine. It will get tested more after this week because I will be on vacation for the rest of the month. My Gladiator is a 2nd vehicle that doesn't get used much. My main vehicle is a 2017 Jeep Wrangler.
My JTR build date is 8/2022
Mileage when accord was 396
Only happened once
Codes P0300 and P00FD

 

[ShadowsPapa]

I wish I knew with certainty what fixed the single cylinder misfire I was having.
The tech swapped coil packs with the adjacent cylinder to see if the issue followed the coil pack, and it disappeared completely and hasn't been back.
The problem is that's also when they did the Z37 flash, so that further clouds the science.
Was it just a poorly seated coil pack? Did the PCM flash lower thresholds or change some timing or firing parameters? Combination?

Whatever it was in grateful and glad to not have that to worry about.

And it could have been a CONNECTION.
I've seen people replace parts when I knew the issue was a connection - they insist - no, the PART fixed it because it's fine now. What do you do when you replace electrical parts? Yeah, you have the connections apart. And often times, especially with low current connections, a tiny thin layer of oxide you can't even see is enough to cause issues.
So you have three possible causes - and it's the reason I hate it when 10 things are done to a vehicle all at the same time. You have no idea which one CAUSE the issue that started after the work, or in this case - what fixed it?
Very possible the flash! I mean - it was intended as a fix..............
And - a PCM flash does some other stuff - like forcing relearns of certain areas.
In my case if they had done a flash it would have resolved my misfire because it was "learn" associated - cam/crank positioning. (as it was their work reduced my mpg by about 1. I was better off with the weird misfire LOL)

 

[ShadowsPapa]

I was using my Jeep for for Christmas shopping visiting many different places, when we were leaving the last store the check engine light came on while still in the parking lot. I never experienced any running problems.

Replace the computer ? Whoa, I question THAT diagnosis.

That's how mine acted - it started at 56 (yes, FIFTY SIX) miles, 3 days after picking it up.
I went into Bass Pro for some coon traps and came back out and it started fine, and was fine until I started to move it out of the lot. LOW RPM, idle and just off idle. It didn't feel rough, and it came out of it in a minute or so. It was thoroughly warmed up, I stopped to buy the traps, back out in 30 minutes or so - that's when it happened.
Then it happened again after Church - parked for 45 minutes - this time it was REALLY rough.
Then it happened twice driving to Florida - stopped at a rest stop - back out in 20 minutes and it did it then again in Florida after unloading out stuff into the hotel - about 30 minutes, we went to eat - misfire when restarting.

No flash needed.
There is a TSB for this - they need to force a cam/crank difference relearn. Mine had not learned the cam to crank relationship - said not yet learned. They triggered a relearn and so far, it's golden. No more misfires.
They said my symptoms matched the TSB near perfectly.

 

[Idlethunder]

Check JSCAN for CCDIFF and similar, like cam crank, etc.

Not having much to do at home today I put around 100 highway miles on the Gladiator. After starting it for the first time I pulled out of the driveway and had the misfires shown in the first screenshot within the first two miles. After that none of the numbers went up more than a couple per cylinder. About 30 minutes later I pulled into a car wash and spent about 20 minutes cleaning out the jeep. When I reconnected Jscan and pulled back out on the road it showed 0 misfires for the entire trip home. I sat here and watched a 30 minute show tv and left again getting the second screenshot within the first 5 miles then only a couple more after that for the next 20 minutes. I spent about 30 minutes in a restaurant then got 0 again on the drive home. No sign of the misfires I got a couple days ago after driving 30 miles then sitting for about half an hour.

From what I read in the posts about yours, it sounds like they were very random. Tomorrow morning I’ll call my service department and ask about forcing the cam/crank difference relearn and see what they can find. Other than that, my plan is to keep monitoring and see if they happen after it sits for a while again.

 

[ShadowsPapa]

From what I read in the posts about yours, it sounds like they were very random.

Yes.
Very.
It happened at 56 miles, then it didn't happen again for a couple of weeks or so. That was in July.
Then it was perfect until mid-September and it happened twice in 2 days - then not again.
So there were many drives between - many weeks between, heck, even over a month in between incidents. I kept my bluetooth adapter connected and my phone set up almost every drive trying to catch it in the act. About the time I gave up and put things away - it happened again.
Smooth as silk most of the time - 99% of the time, really. And two times it wasn't even rough feeling - it set the CEL and jscan showed misfires but I didn't feel them. One time the engine shook hard! I mean it was like running a 4 on 3 cylinders it was shaking badly. At that time my math figured that for the time it was doing that, based on the number of misfires, the RPM and the length of time - #2 didn't fire at all for all that time - at or close to 100% misfires.

 

[BearFootSam]

And it could have been a CONNECTION.
I've seen people replace parts when I knew the issue was a connection - they insist - no, the PART fixed it because it's fine now. What do you do when you replace electrical parts? Yeah, you have the connections apart. And often times, especially with low current connections, a tiny thin layer of oxide you can't even see is enough to cause issues.
So you have three possible causes - and it's the reason I hate it when 10 things are done to a vehicle all at the same time. You have no idea which one CAUSE the issue that started after the work, or in this case - what fixed it?
Very possible the flash! I mean - it was intended as a fix..............
And - a PCM flash does some other stuff - like forcing relearns of certain areas.
In my case if they had done a flash it would have resolved my misfire because it was "learn" associated - cam/crank positioning. (as it was their work reduced my mpg by about 1. I was better off with the weird misfire LOL)

My wife drove our Subaru to a park and then it wouldn't restart. I showed up with jumpers and gave it a hot shot, no dice. I checked the codes and saw that it was the bank 1 cam + crank position sensor. "How odd both of them are bad at once?" So I swap cam position sensors between banks, nothing. I replaced both cam and crank position sensors sure it would fire up, nothing. In my frustration as I scoured the engine bay I spotted a loose lead down on the back side of the engine near the firewall. I pushed it in and gave it another go - fired right up.

Diagnosis - when the delear replaced my motor due to a failed oil consumption test the techs must have failed to fully seat the lead. A few weeks of jostling and it fell loose. The bad news was that I couldn't return $400 of used sensors, c'est la vie.

 

[Idlethunder]

Yes.
Very.
It happened at 56 miles, then it didn't happen again for a couple of weeks or so. That was in July.
Then it was perfect until mid-September and it happened twice in 2 days - then not again.
So there were many drives between - many weeks between, heck, even over a month in between incidents. I kept my bluetooth adapter connected and my phone set up almost every drive trying to catch it in the act. About the time I gave up and put things away - it happened again.
Smooth as silk most of the time - 99% of the time, really. And two times it wasn't even rough feeling - it set the CEL and jscan showed misfires but I didn't feel them. One time the engine shook hard! I mean it was like running a 4 on 3 cylinders it was shaking badly. At that time my math figured that for the time it was doing that, based on the number of misfires, the RPM and the length of time - #2 didn't fire at all for all that time - at or close to 100% misfires.

Since putting 100 very aggressive highway miles on it last Sunday and using Jscan to do a cam/crank relearn Monday evening, the misfires from a cold start have improved to the point of being almost nonexistent. I am getting between 0 to 20 across all cylinders now after it has been sitting for an hour or more. That’s good, I can live with that. The problem now is that it acts almost exactly like yours was. Three times this week I’ve used it to run errands for work and each time have driven approx. 50 miles. All three times it has had between 200 and 250 misfires after the initial 25 mile drive and having been shut off for 15 to 20 minutes while I was in a store. The attachments show the count and the temps from yesterday. Yesterday was the first time I’ve felt them and it happened within the first couple of minutes after pulling out of the parking lot. It shuddered for maybe 15 seconds and the MIL came on and flashed a few times then went off and it ran smoothly for the rest of the drive. Before shutting it off, Jscan indicated the P0300 code but once it was turned and sat for a couple of hours, the code no longer shows up.

I am waiting for a callback from my service department with the hope of getting it in between Christmas and the New Year but I am definitely to the point of letting them keep it for a few days to try to sort out. When I used Jscan to do the cam crank relearn, it was immediate and the engine RPMs did not change. From what I have read, when it is done by a dealership, it takes a couple of minutes, and the RPMs will increase during the reset. When they did your relearn, were you able to watch it being done?

 

[ShadowsPapa]

Since putting 100 very aggressive highway miles on it last Sunday and using Jscan to do a cam/crank relearn Monday evening, the misfires from a cold start have improved to the point of being almost nonexistent. I am getting between 0 to 20 across all cylinders now after it has been sitting for an hour or more. That’s good, I can live with that. The problem now is that it acts almost exactly like yours was. Three times this week I’ve used it to run errands for work and each time have driven approx. 50 miles. All three times it has had between 200 and 250 misfires after the initial 25 mile drive and having been shut off for 15 to 20 minutes while I was in a store. The attachments show the count and the temps from yesterday. Yesterday was the first time I’ve felt them and it happened within the first couple of minutes after pulling out of the parking lot. It shuddered for maybe 15 seconds and the MIL came on and flashed a few times then went off and it ran smoothly for the rest of the drive. Before shutting it off, Jscan indicated the P0300 code but once it was turned and sat for a couple of hours, the code no longer shows up.

I am waiting for a callback from my service department with the hope of getting it in between Christmas and the New Year but I am definitely to the point of letting them keep it for a few days to try to sort out. When I used Jscan to do the cam crank relearn, it was immediate and the engine RPMs did not change. From what I have read, when it is done by a dealership, it takes a couple of minutes, and the RPMs will increase during the reset. When they did your relearn, were you able to watch it being done?

No, they told me about it later when I asked how they got it resolved so quickly (I expect them to have it until the next day)

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