Engine tune up - running rougher now?

A

agentmm

New member
I have used this forum many times for tons of info. Downloaded the app recently for garage reference. This will be my first post though.

08' Wrangler threw up the p0302 code "cylinder 2 misfiring".
Did all spark plugs, wires and coil job because she has 100,000 miles and I don't know when it was done last.

Fired her up and its running rougher than before the job.

Do we have go-to reasons why its worse after the work?

Thanks for your help


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agentmm said:
I have used this forum many times for tons of info. Downloaded the app recently for garage reference. This will be my first post though.

08' Wrangler threw up the p0302 code "cylinder 2 misfiring".
Did all spark plugs, wires and coil job because she has 100,000 miles and I don't know when it was done last.

Fired her up and its running rougher than before the job.

Do we have go-to reasons why its worse after the work?

Thanks for your help


Sent from my SM-G920W8 using WAYALIFE mobile app
Click to expand...

did you doulble check the gap on the plugs and make sure you connected the wires from plug to coil in the proper order?

also try your old coil, possible you got a bad coil.

other things that cause that code:

crankshaft positioning sensor

bad fuel injector
 
Maybe the gaps on the plugs weren't right? I bought pre-gapped champions and one was bad. Also maybe one of your wires isn't clipped on perfectly. I had one I thought was good, but needed a bit more fight before I heard the click.


Sent from my duck blind.
 
Duely noted about the plugs/connections and the coil.

I gapped all the plugs before install. 050.
Hoping I did that properly. Honestly not sure even though thats a laughable joke to you guys.

Will reinstall the old coil. Follow up to come...

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When you got new plug did you get double platinum plugs? Jeep used a dual spark setup so non double platinum plugs will not run properly
 
Some plugs you cant gap. Like iridium I believe. They are preset and have a tiny electrode. Just bringing this up in case possibly you didnt know that and bent an electrode while trying to gap. Im sure thats not the issue but throwing it out there just in case

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agentmm said:
Duely noted about the plugs/connections and the coil.

I gapped all the plugs before install. 050.
Hoping I did that properly. Honestly not sure even though thats a laughable joke to you guys.

Will reinstall the old coil. Follow up to come...

Sent from my SM-G920W8 using WAYALIFE mobile app
Click to expand...

We're not messing with you.


Sent from my duck blind.
 
cozdude said:
When you got new plug did you get double platinum plugs? Jeep used a dual spark setup so non double platinum plugs will not run properly
Click to expand...
I did not know that.

I got the NGK g-power.
Dude at Canadian Tire looked them up for this model (their ipad in the aisle was broken....where the F did the simple books go?)

Thats worth replacing the plugs

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cozdude said:
When you got new plug did you get double platinum plugs? Jeep used a dual spark setup so non double platinum plugs will not run properly
Click to expand...
What can you reference that supports this? I googled it and lots of folks are using g power or iridium plugs. E3's or stock. No mention of dual spark setups

Thanks

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agentmm said:
What can you reference that supports this? I googled it and lots of folks are using g power or iridium plugs. E3's or stock. No mention of dual spark setups

Thanks

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Click to expand...

The oem plugs (on the 3.8 motor) is champion dual platinum plugs. The motor uses 3 coil packs for all 6 cylinders.

So let's talk about companion cylinders 1 and 3. When cylinder 1 fires it goes from the center electrode to the outer electrode and grounds to the motor. When cylinder 3 fires it fires from the outer electrode to the center electrode and returns to the coil pack. If you you compare companion cylinders together you will see that one electrode will be gaped more than the other after the same amount of mile due to this (usually the cylinder that fired from the outer to inner electrode like cylinder 3). It will also cause fly back voltage to the pcm which is not good if you don't use the proper plug like and iridium plug.
 
These are the plugs I put in my 3.8. As cozdude says they are double platinum. Actually didnt know that. If I remember right these were preset. No gap requiredScreenshot_20170114-180844.jpg

sent from my Illudium Q-36 Explosive Space Modulator
 
I stand corrected than thanks. Looking at the electrode on these its not what I was thinking anyway. Ive changed so many plugs on different cars I couldnt remember. Sorry for the misinformation OP

sent from my Illudium Q-36 Explosive Space Modulator
 
I've tried the V-power, E3 and I think it was bosch that makes the +4 ..each one made my 2010 performance worse, the E3 was the worst of the bunch - this was all within 3 months as I was trying to squeeze more out of the 3.8.
it ended up squeezing more money out of my wallet :doh:

I run an aftermarket coil and wires and found the OEM plugs work best.

I always check the gaps, even if they say pre-gapped cause I have OCD and I usually find a bad gap
 
I bought some Champion double platinums. I gapped them appropriately (took care there).

No improvement. Still knocking and missing.

It was suggested at the beginning of this thread that it could be the crankshaft sensor.
Picked one of those up...installed it.

No improvement.

Tested the old coil with new plugs and wires. Same deal. Its not the coil.

Might buy an EGR cleaning pack next and fuel injector cleaner.

Is there anything else that comes to mind?
Thanks for your help thus far


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