01 XJ 4.0 P0304 after warm.
#1
Newbie
Thread Starter
Join Date: May 2016
Location: Ohio
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0
01 XJ 4.0 P0304 after warm.
I have an 01 XJ Sport with the 4.0. I have replaced the head with a new one with the heavier casting. Before the head replacement it ran fine. Now on cold startup it runs great, no issues but after about 10 minutes of driving it develops a bad miss and throws P0304. Since then I have installed new Champion plugs, new coil rail and rebuilt Bosch injectors. I clear the code, cold startup, runs great until warmed up again then code and miss are back. It only misses and throws the code while warm, normal operating temperature. I have read a lot about the heat soak for #3 but can it also cause that in #4? Or am I missing something else? Oil and coolant look good. I love the Jeep, no rust, 210K miles, 4.5" Rough Country lift on 31" M/Ts, roof rack with KCs, but I am losing patience. I have searched the forums and found a lot of great answers but nothing too specific, maybe someone has had the same thing happen.
#2
Junior Member
Join Date: Apr 2013
Location: TX
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0
Doesn't sound like heat soak (in the traditional 00-01 XJ sense we're all used to) if it's happening while running. What coil pack did you use? Mopar?
Try swapping the injectors from cyl 3/4 and see if it repeats or the code moves with it. If no difference, do the same for plugs. If still no difference, i would think it to be thermal failure of a sensor or new component (like the coil pack). Not sure if the new head being out of tolerance could cause this, so I won't opine on that...
Try swapping the injectors from cyl 3/4 and see if it repeats or the code moves with it. If no difference, do the same for plugs. If still no difference, i would think it to be thermal failure of a sensor or new component (like the coil pack). Not sure if the new head being out of tolerance could cause this, so I won't opine on that...
Thread
Thread Starter
Forum
Replies
Last Post
rangermonroe
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
7
08-05-2016 06:56 PM
RickJames Bish
Modified XJ Cherokee Tech
7
03-26-2016 10:48 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)