Thanks in advance, I'm new to this forum.
I have a 2013 unlimited, I purchased with 106,0000 miles and no engine light. Probably 300 miles into it it threw the engine light, P0306, cylinder 6 misfire. I went through the painstaking process of replacing the plugs and coil packs (did all 6 since I was in there with this mileage). I did notice in the process that the cylinder 6 coil pack was an aftermarket not matching the other 5 so I'm guessing old problem......
Cleared code with my scanner , all good.
For a few hundred miles, threw code again.
Cleared it, good for maybe 100 miles, threw, cleared.
Has now been 100-150 miles with no check engine light.......
Jeep runs fine (and has since purchased), very curious if anyone has any suggestions? Should I be concerned?
Again, thanks for any help with this.

 

There is an extended warranty on 2012-2013 Pentastar motors for left bank cylinder head issues. 10 years or 150,000 miles. If your motor is throwing that code and also ticking you might have this issue. https://www.torquenews.com/106/chrys...powered-models

 

https://www.pentastars.com/engines/repairs.php

 

And also this which notes your P0306 code… https://www.carcomplaints.com/news/2...warranty.shtml

 

Do you have Jscan app by chance? I know you can monitor the cylinder misfires realtime with that. I think even though it hasn't thrown the code again it might be useful to see the misfires actually being thrown. The code doesn't get thrown until it's misfiring 2-3% of the time I believe. Just because the code isn't throw doesn't mean it's not misfiring a good bit. I think with that constant issue in #6 I'd be a little concerned about the head as Niteshooter is highlighting.

 

I appreciate the input. So today it threw engine light, P 0300.......random/multiple cylinder misfire detected, starting to worry me. Again, new coil packs and spark plugs.
Guess I'll start chasing vacuum system for leaks and see if I can figure out how to check fuel rail pressure.
I'm in rural Colorado, real shortage of decent mechanics in the region but maybe this is worth a dealer diagnosis....

 

Thanks for the Jscan tip, awesome app! Do you know where I would go in the App to monitor cylinder misfires?

 

when you get it linked up, you can click on the "live data" button that is in the middle of the main screen. What pulls up is a blank page. click the orange button with dots at the bottom. In the search bar at the top you can just type "misfire" and it will filter things out. put a checkmark in the boxes for cylinders 1-6 and then hit the green "ok" button at the bottom which will return you to the previous page. Once you hit the green arrow button on that page it should begin monitoring.

You have to do this each time you start the vehicle which is a bit of a pain, though if you have already taken the jeep for a drive and noticed an issue, when you link up the jscan and begin monitoring with the jeep still running it will read all the misfires that have been logged during that drive (ie...it doesn't just start monitoring from that point forward). Hopefully it is at least helpful to see what is actually being logged by the computer. There is a plethora of data that can be monitored with the app.....it's a bit overwhelming. Sometimes it's just about getting in and playing around with different features in there when you have nothing better to do.