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Unread 11-19-2013, 04:50 PM   #1
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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Unread 11-19-2013, 04:55 PM   #2
copmedic309
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1995 XJ Cherokee 
 
Join Date: Sep 2013
Location: Woodbury, NJ
Posts: 65
Try changing your coil pack and your CPS. See if that helps.
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Unread 11-19-2013, 07:52 PM   #3
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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Unread 11-20-2013, 08:39 PM   #4
Kalali
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2000 XJ Cherokee 
 
Join Date: Apr 2012
Location: Ocean, NJ
Posts: 550
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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Unread 11-20-2013, 09:10 PM   #5
mikehenya
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2004 LJ Wrangler 
 
Join Date: May 2010
Location: ohio
Posts: 9
I changed the TPS right before posting. Anything else I should look at?
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Unread 11-24-2013, 08:11 PM   #6
mikehenya
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2004 LJ Wrangler 
 
Join Date: May 2010
Location: ohio
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Anyone?
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Unread 11-24-2013, 09:01 PM   #7
bigbill888
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1996 ZJ 
 
Join Date: Nov 2009
Location: michigan
Posts: 968
pull #6 plug and see what ya got going on.
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Unread 11-24-2013, 09:10 PM   #8
mikehenya
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2004 LJ Wrangler 
 
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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