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Old 02-17-2017, 06:12 AM
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Progressive Misfire - P0305

Hi Folks,

Noticed a small misfire which initially went away after about 20 seconds after start but didn't throw any codes.

It's now persistent and this morning finally gave me P0305 so cylinder 5 plug/coil is primary suspect.

I've got plugs and a coil on order - is there anything else which could potentially throw this code if swapping plugs and coil doesn't work?

I've read about the lifters but that is all else I can find.

It is LPG also and the misfire is present on LPG or normal (wet) fuel.

Cheers !

Paul.

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Old 02-17-2017, 07:21 AM
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Re: Progressive Misfire - P0305

Did you already swap the plug and coil from cylinder #5 with an other, to see if the fault follows?
So the problem is not fuel related. You could also try a seafoam treatment (or an other product which removes carbon buildup). A sticking valve due to carbon buildup on the valve stem could be the problem. Best is to feed the cleaning fluid through the brake booster vacuum line, without the engine stalling, and then shut the engine down and let the fluid do its work for an hour or so. Then take the jeep for a spin, but be aware that a lot of smoke will come from the exhaust. Sometimes this treatment must be done more then once to get the stems real clean.
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Old 02-17-2017, 08:55 AM
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Re: Progressive Misfire - P0305

Cheers for the response Frank.

I won't have the parts until monday and I'm away most of the weekend but hopefully if the weather allows I'll swap some parts around on sunday to see if the fault follows the coil/plug and replace when the new parts arrive.

I'll keep in mind the seafoam treatment should all else fail.

I'll let you know how it goes!!

Cheers

Paul.
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