15 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHStrange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Reported repair
Clean maf and throttle body and this
Reported resolution
1
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 report a fix
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 fix
I cleaned the MAF and throttle body and this resolved the issue.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Read full discussion summary
Leading evidence: 'Clean maf and throttle body and this' (1 discussions report resolution; 0 report an unsuccessful attempt). Across 1 matching discussions, the most frequently mentioned possible cause is 'infamous air/oil separator' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Clean maf and throttle body and this' (1 discussions). For that action, 1 discussions report a resolution and 0 report an unsuccessful attempt. The most frequently reported fix is 'Clean maf and throttle body and this', supported by resolution reports in 1 discussions. 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.
Combined work: Clean throttle body + Replace air/oil separator
Reported resolution
1
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 report a fix
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 fix
Replaced the air/oil separator, cleaned the throttle body again which allowed it to idle around 700-800 consistently. It's been a week and no further issues so I suspect it was the air/oil separator from the start which prevented the throttle body to close in the first place.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
infamous air/oil separator
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
Turned out to be the infamous air/oil separator that I've been reading about on this forum.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Clean inside and out
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.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Clean throttle body
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
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.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Combined work: Clean throttle body + Replace air/oil separator
1
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that report a fix
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 fix
Replaced the air/oil separator, cleaned the throttle body again which allowed it to idle around 700-800 consistently. It's been a week and no further issues so I suspect it was the air/oil separator from the start which prevented the throttle body to close in the first place.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
air/oil separator
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
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
It's been a week and no further issues so I suspect it was the air/oil separator from the start which prevented the throttle body to close in the first place.
Strange Idle Behaviour - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Combined work: Clean throttle body + Replace air/oil separator
1
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that report a fix
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 fix
Replaced the air/oil separator, cleaned the throttle body again which allowed it to idle around 700-800 consistently. It's been a week and no further issues so I suspect it was the air/oil separator from the start which prevented the throttle body to close in the first place.
Strange Idle Behaviour - 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 · 1 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T144035Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
This being my first Porsche I would defer to you experienced owners. I have a strange idle behaviour once the vehicle warms up to operating temp: At stop, it drops to ~600 then bumps up to ~750 .... rarely it will kick up to ~1100 each time it returns to ~750. I have heard the MAF sensor mentioned in multiple posts dealing with multiple issues, but I don't know if this would be one of them. There is no smoke, no other symptoms. I use ethanol free Shell V Power petrol and STP Octane boost .... 2001 S .... everything stock.
I appreciate any thoughts on what this might be and the best was to troubleshoot.
Thanks!
You may want to make 100% sure you have the correct MAF. They all look pretty much the same but their sensor characteristics have to be matched to your particular car. The 2000 year is a cross over year.
This is from the Pelican DIY article. Link here Porsche Boxster Mass Air Flow Sensor (MAF) Replacement and Troubleshooting - 986 / 987 (1997-08) - Pelican Parts Technical Article
Porsche Part # BOSCH Part # Application Notes
996.606.123.00 0-280-217-007 1997-99 All Boxsters Sensor for use with cable throttle cars
996.606.124.00 0-280-218-009 Early 2000 Boxster / Boxster S Original sensor for E-gas cars
(thru Boxster 2.7L Chassis #98 6YS 62 0414 and #98 0YU 62 5099)
(thru Boxster S 3.2L Chassis #98 0YS 66 0257 and #98 3YU 66 2413)
986.606.125.00 Mid 2000-04 Boxster / Boxster S First updated sensor for E-gas cars
(discontinued and replaced with version 125.01 below)
986.606.125.01 0-280-218-055 Mid 2000-04 Boxster / Boxster S Latest updated sensor
987.606.125.00 0-280-218-145 2005- All Boxster / Cayman Integrated housing design
Because there was a fair bit of work done (below) I will test for a vac leak. I'm assuming this is a factory installed MAF, so it's either dirty (not cleaned when the work was done) or a clamp was not tightened properly/missed when reinstalling the throttle body and plenum.
"Cabin Air Filter: Inspected and replaced with charcoal embedded Mann filter
Engine: Inspected and replaced Mahle air filter. Hoses and belts inspected for cracks. Oil and oil filter replaced with Hengst filter and Mobil 1 0w40 Synthetic. New drain plug washer installed. Slight oil seapage between transmission and engine. Rear main seal was replaced during IMS retro kit install. Oil filter inspected for debris with none present.
Throttle body: Removed and inspected. Slight residue buildup on butterfly. Throttle body and plenum cleaned inside and out. Computer calibration completed.
Oil/air separator: No abnormal oil residue in throttle body or plenum.
Spark Plugs: Replaced with Bosch 7413 plugs.
Coil pack check: Inspected for cracks.
Engine bay check: Cleaned with damp rag and inspected.
"
No CEL (have not checked if there are 'hidden' codes - sorry I don't know the term used when there is a code in the history but no light on the dash). I thought maybe the idle is affected when I depress the clutch, but I never considered the brake involvement. I'll check the connections (as the throttle body was cleaned in Feb) and clean the MAF to see if that changes anything.
I just experienced almost the same problem and mu local Indy shop is a little baffled.
When I start up the motor, idle ranges from 1,000 to 500; back and forth. After taking to local shop, mechanic found the rough idle goes away after disconecting the MAF. No codes. A second and third MAF were installed with no change.
The suspected gremlin is a vacuum leak; but I need some clues as to where to look
Any tips/ suggestions will bee greatly appreciated...
I had the exact same issue on my '02 S last week. Idle would go up to 1500 then down to 800 on it's own without my foot on the gas. My local garage pulled code P0507 on the diagnostic (idle control at stop) so they removed and cleaned throttle body. All was well for about 24 hours and then all hell broke loose! While waiting at a red light idle starting racing again and white smoke began billowing out the tailpipe like a giant refer from a Cheech & Chong movie! Turned out to be the infamous air/oil separator that I've been reading about on this forum. Returned to garage and mechanic found 15" of vacuum at the dipstick when there should be no more than .25" at any time according to him. Replaced the air/oil separator, cleaned the throttle body again which allowed it to idle around 700-800 consistently. It's been a week and no further issues so I suspect it was the air/oil separator from the start which prevented the throttle body to close in the first place. :ah:
Local Indy found an InterceptLink Air Flow Meter Correction module wired to the CPU
See pic
Also replaced Oil seperator and air filter; runs like new car !
I’ll upload a pic later...
My HC results in smog tests have been near the cut off limit the past 4 times the car was smogged; wondering if this device caused that too ?
This is a source reference. Confirm exact model applicability in the original material.
