4 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHOccasional rough running
Reported or suspected cause
transient and only lasts 30 seconds or
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
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 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
The issue is transient and only lasts 30 seconds or so before the engine gets back to working normally, which in these cases didn't leave me the time to stop and check the idle.
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
The issue is transient and only lasts 30 seconds or so before the engine gets back to working normally, which in these cases didn't leave me the time to stop and check the idle.
Leading evidence: 'transient and only lasts 30 seconds or' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'transient and only lasts 30 seconds or' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check idle' (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 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
I've ordered some MAF cleaner and cleaned the MAF (and the ICV while I was at it) but I doubt it'll solve the issue.
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
Changed the injectors to the 996.2 style injectors 2 months ago, although I did notice an improvement for how "balanced" the engine seems to run at low RPMs, but the random rough idle still kept on until I recently changed out the MAF sensor with a new one.
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
The issue is transient and only lasts 30 seconds or so before the engine gets back to working normally, which in these cases didn't leave me the time to stop and check the idle.
Replace ( cheap and easy) and never had the problem
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
Sounds crazy but a Rennlist member told me to replace ( cheap and easy) and never had the problem again.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Check idle
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
The issue is transient and only lasts 30 seconds or so before the engine gets back to working normally, which in these cases didn't leave me the time to stop and check the idle.
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
Changed the injectors to the 996.2 style injectors 2 months ago, although I did notice an improvement for how "balanced" the engine seems to run at low RPMs, but the random rough idle still kept on until I recently changed out the MAF sensor with a new one.
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
What happens is the engine will start to run a little rough and feel like it's down on power and doesn't really want to rev, a little like an engine that's about to die due to an empty tank.
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
I'm looking for some help to diagnose an intermittent rough running on my 1998 3.4 996 (manual coupe, if that matters), which occurred twice over the last 600 miles or so.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
transient and only lasts 30 seconds or
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
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
The issue is transient and only lasts 30 seconds or so before the engine gets back to working normally, which in these cases didn't leave me the time to stop and check the idle.
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.
4 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.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
That switch gets worn out where when you brake the switch doesn't go back to normal.
Hi all,
I'm looking for some help to diagnose an intermittent rough running on my 1998 3.4 996 (manual coupe, if that matters), which occurred twice over the last 600 miles or so.
What happens is the engine will start to run a little rough and feel like it's down on power and doesn't really want to rev, a little like an engine that's about to die due to an empty tank. The issue is transient and only lasts 30 seconds or so before the engine gets back to working normally, which in these cases didn't leave me the time to stop and check the idle. No codes, no lights.
Here's what both occurrences had in common as far as conditions:
-driving somewhat dynamically in twisty mountain roads
-dry weather, once at around 2000ft elevation, the second around 6 000
-engine fully warmed up, with the needle about 1/8th of an inch from the second temp bar
-tank almost full with fresh high octane fuel
-revs around 2-3000 rpm
I've ordered some MAF cleaner and cleaned the MAF (and the ICV while I was at it) but I doubt it'll solve the issue. Coils & plugs are almost new, lifters are new, variocam pads too.
Any ideas?
I had that happen with my '05 997.1. Loss of power once in a while. Ended up as the brake peddle switch. Sounds crazy but a Rennlist member told me to replace ( cheap and easy) and never had the problem again. That switch gets worn out where when you brake the switch doesn't go back to normal. Other members may comment on this! Good luck!
I too am battling an intermittent rough idle in my 1999 C4 manual coupe, noticed only when the engine was hot and in stop & go traffic. Changed the injectors to the 996.2 style injectors 2 months ago, although I did notice an improvement for how "balanced" the engine seems to run at low RPMs, but the random rough idle still kept on until I recently changed out the MAF sensor with a new one. After ~1000 miles, so far so good, but havent had it really hot weather in stop and go traffic just yet. New coil packs, new crank position sensor, cleaned throttle body, and vacuum leak checks were all done prior to this issue as well. Will use the durametric to make sure my fuel trims are within spec.
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