Cylinder 1 Misfire - Tried Everything - Need Help

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Mar 30, 2012 | 02:39 PM

Flash1034

Thread Starter

Member

Joined: Jun 2011

Posts: 146

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From: Southern California

Year: 1997

Model: Cherokee

Engine: 4.0 Liter

Cylinder 1 Misfire - Tried Everything - Need Help

I have a rough idle, like a miss, and it keeps throwing a P1301 (Cilinder 1 Misfire) Code. I have replaced the spark plugs with Champion Copper, the CPS, Wires, Rotor, Distibuter Cap, Used Seafoam, Used Techron, even a new Coil.

Seems to run great but idles like crap and throws the code everytimeI drive it. I looked for vacuum leaks and found none. What else could it be? Im at my wits end as this is my daily driver. Has 156k on it. Please help...Could it be a bad valve? Any suggestions?

Thanks,

Flash

Last edited by Flash1034; Mar 30, 2012 at 02:42 PM.

Mar 30, 2012 | 03:09 PM

413maxwedge

Senior Member

Joined: Jan 2011

Posts: 689

Likes: 2

From: Upstate N.Y

Year: 2000.1999,1996

Model: Cherokee

Engine: 4.0

Could be a bad valve.

Mar 30, 2012 | 03:59 PM

Flash1034

Thread Starter

Member

Joined: Jun 2011

Posts: 146

Likes: 0

From: Southern California

Year: 1997

Model: Cherokee

Engine: 4.0 Liter

Quote:

Originally Posted by 413maxwedge

Could be a bad valve.

That means a new head at 450 bucks...bummer.

Flash

Mar 30, 2012 | 05:06 PM

tjwalker

CF Veteran

Joined: Nov 2010

Posts: 5,840

Likes: 117

From: In the middle of Minnesota!

Year: 1999

Model: Cherokee

Engine: 4.0

You still do not have a solid diagnosis. Next thing you need to do is perform a dry/wet (in that order) compression test. It is exactly what a shop would do. Perform it on all six cylinders so you know what is going on with all the cylinders.

The compression spec of the Jeep 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.

Last edited by tjwalker; Mar 31, 2012 at 06:57 AM.