6 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHRough Idle and Check Engine Light flashing on and off
Leading reported evidence
Replace spark plugs
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
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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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
Spark plugs were changed about 5K ago along with fuel filter.
Rough Idle and Check Engine Light flashing on and off
Read full discussion summary
Leading evidence: 'Replace spark plugs' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'spark plug or ignition coil have failed' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace of them at the same time' (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 suspect 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.
Suspected cause
Most likely a spark plug or ignition coil have failed.
Rough Idle and Check Engine Light flashing on and off
Replace of them at the same time
Suggestion or failed attempt
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 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
If one is crack it is highly recomended to replace all of them at the same time.
Rough Idle and Check Engine Light flashing on and off
Replace these)
Suggestion or failed attempt
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 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 · Original poster
Thought maybe it was my motor mounts causing a vibration (need to replace these) but going through the rpm's would be rough/stuttering until about 3k rpm where it would then it smooth out almost like a turbo kicking in.
Rough Idle and Check Engine Light flashing on and off
Run some errands
Suggestion or failed attempt
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 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 · Original poster
Took it for a drive this afternoon for a few miles to run some errands.
Rough Idle and Check Engine Light flashing on and off
Replace these)
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 · Original poster
Thought maybe it was my motor mounts causing a vibration (need to replace these) but going through the rpm's would be rough/stuttering until about 3k rpm where it would then it smooth out almost like a turbo kicking in.
Rough Idle and Check Engine Light flashing on and off
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.
6 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 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: 20261027T184158Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
OK I've got a slight issue with the C4 6 speed manual with 130K miles on it. Took it for a drive this afternoon for a few miles to run some errands. After returning, started the car back up and at the red light noticed the idle was a bit off/rough. Thought maybe it was my motor mounts causing a vibration (need to replace these) but going through the rpm's would be rough/stuttering until about 3k rpm where it would then it smooth out almost like a turbo kicking in. Then I noticed the check engine light come on and off for a few seconds and then the light goes out and then the same thing happens with the CEL for a few more times before I made it home. I do recall there being some uneven idle a few times prior to this incident but only for a few seconds each time.
I noticed that below 3k rpms the power was down, some hesitation and roughness. Fuel pump has never been replaced to my knowledge, nor the fuel pressure regulator or CPS or TPS. Could a faulty fuel pump be detected by a code reader? And would I faulty pump cause the CEL to come on? My initial inclination is that the fuel pump is going bad but I may be wrong. Spark plugs were changed about 5K ago along with fuel filter. Was running fine before today.
Any thoughts/ideas?
Most likely a spark plug or ignition coil have failed. The check engine light will flash when there is raw/unburnt fuel being dumped into the catalytic converter. This can caused extreme damaged to the converter if driven for any long length of time. Need to have the computer scanned to see what cylinder it is and then do some simple test to confirm which coil or plug it is.
Cracked coil would be my first guess. If they have not been replaced, check them for cracks. The hot weather and or rain will trigger inconsistencies in spark.
Most scanners will be fine. Some times really cheap ones can be an issue. Cracked coils can be an issue on the 996. Porsche had a bulletin about replacing all of the coils if they are a certain part number. If one is crack it is highly recomended to replace all of them at the same time.
