Novak Conversions Jeep Wrangler JK radiators

P0301 and rough idle

A

AdamTA1

New Member
Joined
Sep 11, 2025
Messages
3
Location
North Carolina
Hey everyone!

2018 JKU 107k miles 3.6L

Popped a p0301 code a few weeks back but was running fine. Pulled plug 1 and verified it was toast and needed to be replaced. Watched some YouTube vids to prep. Decided since I was that far dug in I would also replace the oil filter / cooler housing due to some leakage I’d seen under the jeep. Replaced all 6 plugs and the oil filter housing on a Saturday. Cleared the check engine light and took it for a drive. Everything seemed to be running great. Next day it was rough at idle (new issue). Under power no issues at all. A few days later threw a p0301 code again.

I’ve ordered 6 ignition coils that I’m going to swap out hoping that’s what it is. I just think it would be strange, if it is the coils, that it wouldn’t have a rough idle before I did the work but it does now.

Any suggestions or things I should check I would appreciate it.
 
BLACKJKU said:
Did you use OEM parts?

Might also try a ECM Reset.
Click to expand...

NGK plugs, I don’t know that the oil filter housing was OEM couldn’t really find a name brand one. It’s all aluminum and everything I was reading recommended that to get rid of the plastic parts that warp.
The coils I’ve ordered are Bosch. I was going to do NGK for those but couldn’t find 6 in stock.
I’ll have to look up ECM reset. I’ve not done that in the past.
 
Chris

Thread 'How to Reset the ECU on a Jeep Wrangler JK'

While there are folks that swear resetting your ECU does absolutely nothing, it's a common practice among automotive enthusiasts. The ECU (Electronic Control Module) "learns" your driving style and the parts in your ride by storing information in its memory, information that it gathers using a number of sensors located all throughout the vehicle. After installing new or performance parts, you can reset the memory in the ECU and force it to "relearn" the vehicle's modifications and your driving style with just a few simple steps, which will allow you to take full advantage of the...
  • Like
 
  • Like
Reactions: AdamTA1 and tJKrider
I'd check your wiring by the coils. From moving the wire harness you could of cracked a wire or check and make sure your harness plugs are snapped in all the way.
 
  • Like
Reactions: BLACKJKU and tJKrider
Sorry for delay in response work has been busy. I tried resetting the ECM and I looked through the wiring. No issues that I saw with the wiring and resetting did not work.
I'm going to try and do a deeper dive this weekend on the wiring just to triple check.
I'll also do the coils swap this weekend, if I can find time.
 
  • Like
Reactions: JeepJeezy and BLACKJKU
Novak Conversions Jeep Wrangler JK radiators
Top Bottom