19 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 erratic idling
Reported or suspected cause
mas air flow sensor, all fine now
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
I had a problem with erratic running, more at higher revs, a multitude of error codes involving PSM, o2 sensors, turned out to be a faulty Mas air flow sensor, all fine now
Leading evidence: 'mas air flow sensor, all fine now' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'mas air flow sensor, all fine now' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Adjust valve timing (when needed) in the variocam system' (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
I didn't want to miss lead you, just wanted to make sure they checked all the codes.
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
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Performed · outcome unconfirmed · Original poster
Warranty has changed both cats and oxygen sensors, which has improved the stability, but idling is still erractic and she has stalled once since her last return from the dealer.
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
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Performed · outcome unconfirmed
In Porsches it is also used (as a factor) to adjust the valve timing (when needed) in the VarioCam System.
Adjust valve timing (when needed) in the variocam system
Suggestion or failed attempt
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 contain suggestions
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Suggestion
In Porsches it is also used (as a factor) to adjust the valve timing (when needed) in the VarioCam System.
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
Warranty has changed both cats and oxygen sensors, which has improved the stability, but idling is still erractic and she has stalled once since her last return from the dealer.
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
We understand the milage to be genuine, although high, we are the second owner, and the first was lucky enough to use her every day up and down a motorway to work, we have seen the history and nothing has shown as a problem, until now.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
mas air flow sensor, all fine now
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
I had a problem with erratic running, more at higher revs, a multitude of error codes involving PSM, o2 sensors, turned out to be a faulty Mas air flow sensor, all fine now
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.
19 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: 20261027T005001Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Can anyone advise please, we have a 99 996 C2 tiptronic, with 82,000 miles on the clock, lovely car but has devolped erratic idling to the point where she would stall, when she has been driven a bit quick. Warranty has changed both cats and oxygen sensors, which has improved the stability, but idling is still erractic and she has stalled once since her last return from the dealer. Any advice as to where to go next would be appreciated, the Porsche computer logs no errors, but I have a sneaky suspicion that it is something to do with the either the temperature sensor, or maybe the injectors, does anyone have any experience with this problem?
Thanks for the reply so quickly, we hate to be ignorant but what is a MAF sensor? it is not one we have come across. We have been trying to get information about the design of the Motronic engine system specific to our car to understand what is going on, so we can eliminate the sensors if necessary one by one?
It measures the air (intake) volume and with the air intake temperature the DME (Motronic control) adjusts the fuel mixture accordingly. In Porsches it is also used (as a factor) to adjust the valve timing (when needed) in the VarioCam System.
The sensor can be easily damaged by moisture, debris, or oil... and as I said, it is the most replaced part of the fuel system.
Thankyou so much, we will now get this replaced as soon as possible we very much appreciate your help and we will keep you posted.
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1999 996 C2
Arctic Silver/Grey leather
18" turbo alloys
sports pack
PCGB
We believe the codes are ok, she has been on the Porsche dealers diagnostic computer 3 or 4 times and everything always shows ok, last time she was 100% perfect, this is why we and the main dealer are stumped as to why she will stall. If you mean some other codes could you explain them please, thankyou.
I didn't want to miss lead you, just wanted to make sure they checked all the codes. That's the highest mileage 996 I ever heard of. I guess the Mass flow sensor could be bad at this point. I will stop by dealer Monday and talk to my mechanic. Maybe he has some Idea.
Thankyou very much for your concern and even more for you taking the time to talk to a mechanic that you know, it is greatly appreciated, and we await for any conclusion or suspicion he may also have, its has now also been suggested that the idle adjuster might be a point to look at?
We understand the milage to be genuine, although high, we are the second owner, and the first was lucky enough to use her every day up and down a motorway to work, we have seen the history and nothing has shown as a problem, until now. We hope to rectify the problem and experience 80,000 further trouble free motoring, although it will take us a lot longer to reach that amount!
I am a mechanic at a dealer and have exsperienced this type of problems many times. I believe the previous reply is correct about the mass air flow sensor. Even with no codes, you can check your TRA's or short term fuel trim. The number should be as close to zero as possible. I believe you have definetly found the right area to start looking.
I had a problem with erratic running, more at higher revs, a multitude of error codes involving PSM, o2 sensors, turned out to be a faulty Mas air flow sensor, all fine now
Thanks to everyone for your advise, it would be so brillant to think we have found the problem, it has been a frustrating time with no-one able to give decisive help,if this proves to be the problem which you guys have pointed out it will show that these types of forums for enthuasists are an absolute godsend! We have now booked her in at our local Porsche dealer for this saturday to have it replaced, so we will keep you posted. Fingers crossed and once again thankyou.
Hi guys, sorry to be a real pain but it is a non solution, with the MAF sensor, I need your help again, any further suggestions???? <img src="graemlins/crying.gif" border="0" alt="[crying]" />
[quote]Originally posted by rugg_man:
<strong>Hi guys, sorry to be a real pain but it is a non solution, with the MAF sensor, I need your help again, any further suggestions???? <img src="graemlins/crying.gif" border="0" alt="[crying]" /> </strong><hr></blockquote>
Hi,
I am not an expert but I have been on these boards for a long time and I have identified two issues you may want to look at (I believe the advise given by others re the MAF was correct as being the #1 possible culprit)
a) Exhaust leaks. They may cause erratic idling.
b) ECU. I had heard before of similar idling problems with Boxsters and an ECU update from the dealer seems to fix the problems. Ask your dealer to re-download the latest ECU program for your car.
Were you running the A/C when you had these problems?
Hi Dimitris
Thankyou for your input,I will ask my OPC for this to be done, you never know? unfortunately it is a process of eliminiation and we will give anything a go. We have not been aware if the A/c is on or off, we will drive her tommorrow and check, what diffrenece would this make? Will keep you posted, thanks again.
</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by rugg_man:
<strong>Just a thought would it make any difference to the possible solution to the problem as she is a tiptronic?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">I do not think the tip has anything to do with the idling issue. But who knows?
The Boxster owners who had this problem mentioned that the problem mostly occured with the A/C on. Why don't take your car for two rides, one with the A/C on and one off and see if this makes a difference?
Let us know ...
We went to our OPC Tuesday and asked about it being recoded, they knew what we meant but had only ever done it to a C4, not a C2 they are going to ask if they is anything avaliable from Porsche?
Regarding the A/c we will drive it and see, thank u.
We are taking it to the OPC on saturday and they are going to keep it for a week, one of their guys is going to drive it to and from work each day and see when and why it happens hopefuly as they will have the computer plugged in on the passengers seat, maybe this will show the problem. They aggree is sound like air getting in but it just a case of where from??
Will keep you posted
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