Bad misfire 4.0 - JeepForum.com

 
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post #1 of 8 Old 11-19-2013, 03:50 PM Thread Starter
mikehenya
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2004 LJ Wrangler 
 
Join Date: May 2010
Location: ohio
Posts: 9
Bad misfire 4.0

Just got a 2000 Cherokee w/ 4.0 , it made it 90 miles home but missed constantly. Ticking seems a little louder than normal. When I got home I changed plugs, new TPS and new IAC. It is running better, but I am constantly getting a "Cylinder 6 misfire. I did an oil flush and am currently running some Techron through it but the miss is still there. Fuel pressure is 45.

I have been driving it locally as much as I can, misfires all the time but also has 2 other symptoms:
It is slow to return to a normal idle
After driving for a little while it starts acting like it is hitting the rev limiter at bout 26-2800rpm's. I have seen these symptoms all over the net, but no solid resolution.
Any thought? Thanks!

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post #2 of 8 Old 11-19-2013, 03:55 PM
copmedic309
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1995 XJ Cherokee 
 
Join Date: Sep 2013
Location: Woodbury
Posts: 65
Try changing your coil pack and your CPS. See if that helps.

Ry.
Rather be tried by 12, than carried by 6.
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post #3 of 8 Old 11-19-2013, 06:52 PM Thread Starter
mikehenya
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2004 LJ Wrangler 
 
Join Date: May 2010
Location: ohio
Posts: 9
From what I have been reading, the 3 coil rail, it will miss fire on 2 cylinders? Not sure if that is true though. I guess I will try CPS next...ugghh
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post #4 of 8 Old 11-20-2013, 07:39 PM
Kalali
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2000 XJ Cherokee 
 
Join Date: Apr 2012
Location: Ocean
Posts: 643
These symptoms do not match a bad coil pack or faulty cps. Aside from the misfire code other symptoms are more like a bad tps.
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post #5 of 8 Old 11-20-2013, 08:10 PM Thread Starter
mikehenya
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2004 LJ Wrangler 
 
Join Date: May 2010
Location: ohio
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I changed the TPS right before posting. Anything else I should look at?
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post #6 of 8 Old 11-24-2013, 07:11 PM Thread Starter
mikehenya
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Location: ohio
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Anyone?
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post #7 of 8 Old 11-24-2013, 08:01 PM
bigbill888
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1996 ZJ 
 
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Location: michigan
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pull #6 plug and see what ya got going on.

96 ZJ Laredo, 4.0, 242, 230K
95 ZJ Limited, 4.0, 242, 140K
98 XJ Sport, 4.0, 231, 140K
All work well
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post #8 of 8 Old 11-24-2013, 08:10 PM Thread Starter
mikehenya
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Join Date: May 2010
Location: ohio
Posts: 9
Quote:
Originally Posted by mikehenya View Post
When I got home I changed plugs, new TPS and new IAC. Thanks!
Plugs just looked normal...
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