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Old 06-06-2018, 02:22 PM
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Join Date: Jun 2018
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Multiple cylinder misfires

Recently had to get emissions done for my 2010 Rubicon, 95000 miles. Fail code came back P0302 which I found out was a misfire on cylinder 2. Figured I would change the spark plugs.

Last night I was only able to get cylinders 1,3,5 done as 2,4,6 were too tight to loosen by hand. Today I could tell the Jeep was running rough, and had a bad idle. The check engine light kept flashing this afternoon so I took it to get scanned. Came back with P0302, P0304, and P0300 (random misfire).

I noticed while taking out the old park plugs that the gap was around 0.07. Specs call for 0.05 which is what I put on the new ones. Since I only did half the plugs, could this be causing the issue? But why would cylinder 4 be misfiring if i didn't even replace it? Could my wires maybe not be fully on making a good connection? Not sure what to do here. Thanks for any help.

HeAVyB101 is offline   Quote
Old 06-06-2018, 10:41 PM   #2
Join Date: Sep 2016
Posts: 108
Replace the other plugs, make sure the wires are all secure, clear the PCM and drive it.
Don't panic just yet.
Let us know how it turns out.

lowflyer001 is offline   Quote
Old 06-07-2018, 06:39 AM   #3
Join Date: Jun 2018
Location: Davis Park, Fire Island
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When mine did that the computer had went bad. Replaced it and runs like a charm except for Death Wobble and Neutral Safety Switch issues..
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Old 06-07-2018, 06:48 AM   #4

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As lowflyer said: Finish the tune up, clear the codes and drive it before panicking. How many miles are on the Jeep? When was the last time the coil pack was changed? Plugs should not be finger tight, they should not come out by hand. That could be your problem right there.
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