15 captured repliesPartial discussion capture · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 slightly erratic idle.
Leading reported evidence
Check over
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
A couple had noticeable cracks when removed but almost all of them showed some very slight hairline splits beginning when cleaned up/checked over.
Leading evidence: 'Check over' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check /rule out the basic stuff/service items first 8)' (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
Can I use carb cleaner on the MAF as well or just give it a wipe down...?
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
Just been into the man cave I used CRC sensor cleaner :thumb:
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
IIRC carb cleaner is a no no as is a wipe down I sure I used a sensor cleaner that will not leave a residue :thumbs:
Check /rule out the basic stuff/service items first 8)
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
I'd probably want to check/rule out the basic stuff/service items first 8)
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.
911uk: 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: 20261026T212127Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Evening all.
I've done a search but can't really find a conclusive answer.
My 996.2 c2 manual has a slightly erratic idle.
Oil pressure is good etc.
It idles around 800rpm and shuffles up and down.
I'm nervous it could be the IMS bearing.
Any insight or advice would be great.
Thanks
Antony.
MAF sensor perhaps my 997 did what just what you describe I took it out and used some sensor cleaner on it ,sorted child's play well it must be I managed it :thumb:
IMS bearing .. erm .. no .. it still runs !
Seriously though .. its not the IMS .
Air leak is the most obvious followed by clean the throttle valve then check for fault codes and what the mixture adaptions are .. done with a tester .
Post results if you have a tester .
...a question for the technicians; using an obd can one confirm that the AOS and vacuum lines are good?
My non technical brain is inclined to think that a strong idle vacuum reading is a sign of a healthy engine and AOS, and non leaky vacuum lines?
Is my thinking correct?
For example my 996 Gen 2 shows around 24 ish (idle intake vacuum) on a cold idle which is about the same as my newer BMW 630i....
air leak, MAF (try unplugging and see if any difference, I ordered mine with bosch number from a bosch dealer, opc too expensive, and there are many fakes around), AOS (check in intake beyond throttle for oil residue).
I had erratic idle in my C2 about a year ago. I had a few things done at the same time / Crank Angle Sensor / Breather Hose / Battery.
Breather hose was full of splits....maybe worth a look.
Idle is a lot better.
Jim.
The 996 is VERY sensitive to air leaks - any "erratic" behaviour is almost certainly vacuum or general air leak related..... its "consistent" behaviour you need to worry more about..... but even then, it's not always an IMS bearing about to explode and end all life on the planet (despite what various magazine and online articles have said over the years)
So I'm changing the air filter tomorrow and fitting the DT CAI.
I'll clean the throttle valve. Can I use carb cleaner on the MAF as well or just give it a wipe down...?
holy thread resurrection!
chasing vacuum leaks - there are many, many pipes in that engine bay, many of which are almost inaccessible
so is there a common culprit to check first? (Photos / links would be helpful!)
symptoms are:
a very slight idle lumpiness
some hesitation below 2000rpm.
and where do you get CRC cleaner from?
Thats a bit of a needle in a haystack question im afraid .. i can think of many things from a maf sensor to a slight misfire that would cause this .
First things first do you have a tester ?
We need fuel adaptions to see if there is an air leak , we need the rough running or misfire section .. we need the lambda sensor state .. is it switching correctly .
To answer your question though .. no there is no set air leak and the car will compensate for any small air leaks reguardless .. it will richen up the mixture and therefore eliminate the problem basically .
FWIW, although I'd not really had cause for concern the idle is a lot smoother on mine since fitting new coil packs (and plugs).
The originals although not
that
old (replaced at OPC about 5-7 years ago, maybe 20k miles or something from memory) were all degrading to some degree. A couple had noticeable cracks when removed but almost all of them showed some very slight hairline splits beginning when cleaned up/checked over. Certainly worth replacing whilst you're in there - I think the current/updated BERU packs are circa £20/30 each. Didn't have any misfire codes on a basic OBD reader - perhaps the correct Porsche diagnostics would help pinpoint any issues a bit easier?
Quite a common issue I understand due to their proximity to the exhausts and crud/damp from the rear wheels/underneath. I'd probably want to check/rule out the basic stuff/service items first 8)
