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YOUR RESEARCHMisfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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just
Reported cause
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1
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Discussions that report identifying a cause
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Reported cause
I had this problem recently and the cause was just that!
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Leading evidence: 'just' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'just' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check oil filter' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause · Original poster
I had a similar problem weeks after solving this issue, and it was the oil/air separator that had issues.
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Replace 6 coils this weekend and it didn't
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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Unsuccessful attempts
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Discussions
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed · Original poster
I don't think so, I changed all 6 coils this weekend and it didn't change anything.
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Replace after the problem started
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
It did't have major work recently, and the Spark Plugs and Ignition Coils were changed after the problem started.
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
ims, if it's
Suggestion or failed attempt
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Identified cause
1
Suspected cause
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
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Suspected cause · Original poster
I was afraid it was the IMS, if it's that, I was told the car should make a "cling cling" sound similar to a chain touching something.
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Replace coils though…please ask your service technicians
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Discussions that contain suggestions
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Suggestion
I also drives a 2015 porsche bolster which had the same issue-it got resolved by changing the coils though…please ask your service technicians to interchange the coils and see if the coil is the real culprit.you might get error code and the system also allows you to drive.when you swap the coils between misfired cylinders and running cylinders, the error coding must show the shift to previously running cylinders….then its confirmed the issue is with the ignition coils…i did this exercise and confirmed about the coils and got it changed and the issue was resolved.all the best and happy motoring!
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run cylinders, the error coding must show the shift
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I also drives a 2015 porsche bolster which had the same issue-it got resolved by changing the coils though…please ask your service technicians to interchange the coils and see if the coil is the real culprit.you might get error code and the system also allows you to drive.when you swap the coils between misfired cylinders and running cylinders, the error coding must show the shift to previously running cylinders….then its confirmed the issue is with the ignition coils…i did this exercise and confirmed about the coils and got it changed and the issue was resolved.all the best and happy motoring!
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run cylinders….then its confirmed the issue is
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I also drives a 2015 porsche bolster which had the same issue-it got resolved by changing the coils though…please ask your service technicians to interchange the coils and see if the coil is the real culprit.you might get error code and the system also allows you to drive.when you swap the coils between misfired cylinders and running cylinders, the error coding must show the shift to previously running cylinders….then its confirmed the issue is with the ignition coils…i did this exercise and confirmed about the coils and got it changed and the issue was resolved.all the best and happy motoring!
Misfiring cylinders 4, 5 and 6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Coverage and how to read this overview
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
15 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
986Forum: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T154520Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hello Everyone,
I am new to this forum, as I have recently purchased a red 986 2.5 Boxster from 99, with 94k Km.
However, I have some issue with it, and the mechanics I have been to have not helped me up to now, so I turn to the community to help me diagnose the problem.
I have 4 error codes on the car, Random Misfire (P0300), and Random Misfire cylinders 4,5 and 6 (P0304, P0305, P0306). So basically, I have one bank of cylinder that is not working. The car idles with difficulty when cold, and has about 1/3 of the horsepower it should have even hot, but still runs. Even when hot, putting the AC on will stall the engine in idling. When the engine is starting, it randomly makes between 1 and 5 time a big knock, like if you tap two metal parts together, during the first 30 seconds. It also farts dark smoke randomly when cold.
I have changed the Spark Plugs and Ignition Coils without conviction (since it's all 3 cylinders on one bank). I am soon receiving a MAF, but I don't thing it's the issue since it would affect all 6 cylinders.
So I am looking for your experience to help me. I am thinking about injectors (but why 3 on one bank?), air/oil separator (why not all cylinders then?), or head gasket seal?
Do you think that the symptoms indicate one of these problem, or maybe something else that I have not think of ? Maybe one of the thing I listed cannot be the cause and I would waste money changing them now ?
Thank you in advance.
Nounoon
That's odd, I only fart dark smoke randomly when I'm warm.....
Check your oil filter. Any debris at all? I'd stop running it until I had a better idea what's wrong.
Lots of possibilities. It's air, spark or fuel so look at all three. Electrical issues are the first place I would look. Rodent damage to a wire harness? Year? model? mileage? Any recent work done that might have affected one bank?
Best not to run the car until you get some better intel. Misfires tend to kill these engines very quickly.
Do you have a Durametric? Is that the only code you see? How are your cam deviations? How about RKAT readings?
I would also suggest rechecking your wire connections into the packs. These need a little finesse to assure that they are properly seated (making a good connection). I had this problem recently and the cause was just that!
Nounoon, did you resolve this? I have almost exactly the same problem (same codes). Mine starts and idles OK, but misses just off idle until warmed up. I've replaced all plugs and coils, as well as fuel pump and fuel filter for good measure, but I still have this issue.
HI NOUNOON
hello!
I am also new to th forum and glad to see the same feathers!
I also drives a 2015 porsche bolster which had the same issue-it got resolved by changing the coils though…please ask your service technicians to interchange the coils and see if the coil is the real culprit.you might get error code and the system also allows you to drive.when you swap the coils between misfired cylinders and running cylinders, the error coding must show the shift to previously running cylinders….then its confirmed the issue is with the ignition coils…i did this exercise and confirmed about the coils and got it changed and the issue was resolved.all the best and happy motoring!
Hi,
I tried with a OBD-II reader, to check the real time values of the different sensors. The issue on my car was the O2 sensors that where dead, so the car didn't know how much air/fuel to put in the engine. I had a similar problem weeks after solving this issue, and it was the oil/air separator that had issues. Now the car is working well.
I was afraid it was the IMS, if it's that, I was told the car should make a "cling cling" sound similar to a chain touching something.
