P0301 Code and rough idle?
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
my jeep use to do a similar thing. it would start up fine and idle fine until it warmed up. i thought it was my idle air control so i cleaned it out.that didnt do anything so i decided to try and clean some engine grounds and the battery terminals and now it runs fine. something to think about.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
my jeep use to do a similar thing. it would start up fine and idle fine until it warmed up. i thought it was my idle air control so i cleaned it out.that didnt do anything so i decided to try and clean some engine grounds and the battery terminals and now it runs fine. something to think about.
Seasoned Member
Joined: Jun 2012
Posts: 427
Likes: 0
From: Ronceverte WV
Year: 1998
Model: Cherokee
Engine: 4.0 I6
I cringed when I watched that video..... But I trust you folks though. Going to try the water thing. I've tried several things to get rid of my 98s cylinder 6 misfire I'm pretty sure my wires cap and rotor are due anyways. ( already changed the plugs to no avail) I even disconnected my injectors and then my idle got real rough.
But Im going to look into that tsb though.
I do know she's running rich cause my exhaust/intake and donut gasket is wasted. ( Got a felpro one sitting in the hatch now.) Then ( hopefully) my exhaust work will be done.
But Im going to look into that tsb though.
I do know she's running rich cause my exhaust/intake and donut gasket is wasted. ( Got a felpro one sitting in the hatch now.) Then ( hopefully) my exhaust work will be done.
Thread Starter
Senior Member
Joined: Jan 2009
Posts: 640
Likes: 0
From: Tacoma
Year: 2000
Model: Cherokee
Engine: 4.0
I cringed when I watched that video..... But I trust you folks though. Going to try the water thing. I've tried several things to get rid of my 98s cylinder 6 misfire I'm pretty sure my wires cap and rotor are due anyways. ( already changed the plugs to no avail) I even disconnected my injectors and then my idle got real rough.
But Im going to look into that tsb though.
I do know she's running rich cause my exhaust/intake and donut gasket is wasted. ( Got a felpro one sitting in the hatch now.) Then ( hopefully) my exhaust work will be done.
But Im going to look into that tsb though.
I do know she's running rich cause my exhaust/intake and donut gasket is wasted. ( Got a felpro one sitting in the hatch now.) Then ( hopefully) my exhaust work will be done.
Its weird, my CEL is off now. Its been off for the past 2 days. Idle is the same and i can still hear a misfire. Not sure why but the light turned itself off?

I disconnected injectors one at a time last weekend and the idle barely changed. It was weird i thought thered be a big difference.
Seasoned Member
Joined: Jun 2012
Posts: 427
Likes: 0
From: Ronceverte WV
Year: 1998
Model: Cherokee
Engine: 4.0 I6
Yeah when I went to the parts store and got the gaskets and sea foam her cel turned off too. But work has been keeping me very busy and she's getting angry again lol.....
Thread Starter
Senior Member
Joined: Jan 2009
Posts: 640
Likes: 0
From: Tacoma
Year: 2000
Model: Cherokee
Engine: 4.0
Still idles rough regardless though. Is this just electrical?
On a side note i have noticed my mpg's have gone up since i seafoamed it and filled my tank with the fuel system cleaner mixed in. I was only getting about 210 out of a tank before that. And now im already at 180 miles and having over a quarter tank left of that tank.
Last edited by Keaton; Nov 15, 2012 at 06:43 PM.
Senior Member

Joined: Feb 2012
Posts: 627
Likes: 3
From: newjersey
Year: 2000
Model: Cherokee
Engine: I6
any update? i did the water trick in mine and its still rough. how to you get to the engine ground in the back? mine looks pretty grimy but i cant get to it with any tool
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0


