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P0302 Cylinder Misfire in #2 on Wrangler '11

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Old 03-16-2019 | 06:31 PM
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Question P0302 Cylinder Misfire in #2 on Wrangler '11

Hi all,
First time posting! Had a CEL came on a couple of days ago at the same time the low fuel light went on. Checked the code and it's a P0302, it's a 2011 Wrangler Sport (petrol) with 86000 km on it. I've done a bit of reading on these forums and it's clear it could be caused by a number of different parts , the car seems to be running well, idling at around 600RPM, no noticeable loss of power, no spluttering, very occasional light shudder on idle but I can't tell if that's normal (and I'm just being paranoid) or not.

I think I'll start with the spark plugs then the spark plug leads because it sounds like that is a good place to start.

Does anyone have any thoughts on this?

Cheers,
Dave
Old 03-17-2019 | 06:19 AM
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Originally Posted by hynesy
Hi all,
First time posting! Had a CEL came on a couple of days ago at the same time the low fuel light went on. Checked the code and it's a P0302, it's a 2011 Wrangler Sport (petrol) with 86000 km on it. I've done a bit of reading on these forums and it's clear it could be caused by a number of different parts , the car seems to be running well, idling at around 600RPM, no noticeable loss of power, no spluttering, very occasional light shudder on idle but I can't tell if that's normal (and I'm just being paranoid) or not.

I think I'll start with the spark plugs then the spark plug leads because it sounds like that is a good place to start.

Does anyone have any thoughts on this?

Cheers,
Dave
I've never had that code, but like you, that's where I'd start. You might even ask your dealership. They may know the cause to be a common issue and might help steer you in the right direction. I've had vague codes twice that didn't really tell me much. One led to a new catalytic converter and the other to two new O2 sensors.
Old 03-17-2019 | 07:10 PM
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Originally Posted by dmwil
I've never had that code, but like you, that's where I'd start. You might even ask your dealership. They may know the cause to be a common issue and might help steer you in the right direction. I've had vague codes twice that didn't really tell me much. One led to a new catalytic converter and the other to two new O2 sensors.
After speaking to a mate who knows a bit more he suggested I do the following:
  • Check distributor cables/ignition wires are properly connected
  • Check air intake/filter
  • Check spark plugs and visually inspect for dirt/grime, etc
  • Take distributor cap head off and visually inspect for dirt/grime, etc
  • Test distributor cable
I'll post how I go here in case it comes in handy for others.

Cheers,
Dave
Old 03-18-2019 | 02:38 AM
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Originally Posted by hynesy
After speaking to a mate who knows a bit more he suggested I do the following:
  • Check distributor cables/ignition wires are properly connected
  • Check air intake/filter
  • Check spark plugs and visually inspect for dirt/grime, etc
  • Take distributor cap head off and visually inspect for dirt/grime, etc
  • Test distributor cable
I'll post how I go here in case it comes in handy for others.

Cheers,
Dave
I checked the air filter and it had a bit of debris in it, along with being dirty. I've attached a photo of it after I gave it a clean, does it need replacing? When I checked the misfire stays they seemed to have reduced a little with the clean, also noticed a single misfire in #4, not enough to trigger a CEL tho.


What do you think?
Old 03-18-2019 | 05:37 AM
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Sorry to bump this again, but I've had this CEL on for a few days but I'm planning to take it in on Friday (4 more days) as I think I have reached the limit of my skillset. Do you think that will be ok (i.e. won't cause any permanent damage) to wait until then?
Old 03-18-2019 | 07:50 AM
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P0302 is a cylinder 2 misfire and could be due to anything causing low power in that cylinder, most often ignition-related but could be a fuel injector or something else. If the engine seems to be running fine otherwise I wouldn't worry about driving it until your service appointment.
Old 03-20-2019 | 12:33 AM
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Originally Posted by smiller
P0302 is a cylinder 2 misfire and could be due to anything causing low power in that cylinder, most often ignition-related but could be a fuel injector or something else. If the engine seems to be running fine otherwise I wouldn't worry about driving it until your service appointment.
Thanks Smiller!

i did my best to clear the dust and leaves from the filter, firmly pushed in both ends of the spark plug cable and the CEL has gone off after a couple cycles, suspect that's not the last I'll see if it though.

There is no perceivable (to me) performance impact so I'm not super concerned at this stage.

Cheers,
Dave




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