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HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

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5 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHHELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Leading reported evidence

Clean plastic intake tubes

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 · Original poster

cleaned all the plastic intake tubes

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Frequently discussed work

Check electrical connections

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

Re-check the electrical connections that were disconnected/re-connected.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Read full discussion summary

Leading evidence: 'Clean plastic intake tubes' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check electrical connections' (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.

Read captured replies

1 matching discussions · 5 captured posts examined · 0 partial discussions

Compare 4 other evidence results

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

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

cleaned the throttle body with solvent and a brush (did I brake it?)

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Clean throttle body, idle control valve, and mass airflow sensor

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 · Original poster

Cleaned throttle body, idle control valve, and mass airflow sensor with the correct spray cleaner, all of them were very dirty specially the ICV.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Disconnect /re-connected

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

Re-check the electrical connections that were disconnected/re-connected.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Install banjo fitting

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 · Original poster

This is 99 boxster new to me, just bought it a while ago, when i got it it had a typical burned by headers power steering high pressure line and previous owner installed a banjo fitting with clamps that was leaking, so I removed the entire line and replaced with a new one, after doing this the car runs very rough at idle like is running on 4 or 5 cylinders and wants to stall on idle, the car was running great before I replaced the power steering line.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Frequently discussed actions (10)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Check electrical connections

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

Re-check the electrical connections that were disconnected/re-connected.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Clean plastic intake tubes

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

cleaned all the plastic intake tubes

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Clean throttle body

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

cleaned the throttle body with solvent and a brush (did I brake it?)

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Clean throttle body, idle control valve, and mass airflow sensor

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

Cleaned throttle body, idle control valve, and mass airflow sensor with the correct spray cleaner, all of them were very dirty specially the ICV.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Disconnect /re-connected

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

Re-check the electrical connections that were disconnected/re-connected.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Install banjo fitting

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

This is 99 boxster new to me, just bought it a while ago, when i got it it had a typical burned by headers power steering high pressure line and previous owner installed a banjo fitting with clamps that was leaking, so I removed the entire line and replaced with a new one, after doing this the car runs very rough at idle like is running on 4 or 5 cylinders and wants to stall on idle, the car was running great before I replaced the power steering line.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Replace power steering line

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

This is 99 boxster new to me, just bought it a while ago, when i got it it had a typical burned by headers power steering high pressure line and previous owner installed a banjo fitting with clamps that was leaking, so I removed the entire line and replaced with a new one, after doing this the car runs very rough at idle like is running on 4 or 5 cylinders and wants to stall on idle, the car was running great before I replaced the power steering line.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Replace with a new one

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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

This is 99 boxster new to me, just bought it a while ago, when i got it it had a typical burned by headers power steering high pressure line and previous owner installed a banjo fitting with clamps that was leaking, so I removed the entire line and replaced with a new one, after doing this the car runs very rough at idle like is running on 4 or 5 cylinders and wants to stall on idle, the car was running great before I replaced the power steering line.

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Run even better than

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

Ok got it running great, the bad thing is that I do not know what was the problem but is running even better than before

HELP!!! rough idle missfires after work on ps - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Run i sprayed a little engine starter

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

When running I sprayed a little engine starter on the probable sources of leaks and the idle does not change except when spraying close to the air box, which I assume is normal.

HELP!!! rough idle missfires after work on ps - 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.

5 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 · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261027T011819Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi, I need some advise on this thing. This is 99 boxster new to me, just bought it a while ago, when i got it it had a typical burned by headers power steering high pressure line and previous owner installed a banjo fitting with clamps that was leaking, so I removed the entire line and replaced with a new one, after doing this the car runs very rough at idle like is running on 4 or 5 cylinders and wants to stall on idle, the car was running great before I replaced the power steering line. My first impression is that it has a vacuum leak and I checked everything that I disconnected and removed over and over: plastic tube from airbox to throttle body snorkel clamp clamp from tube to throttle body little rubber hose under Throttle body two little plastic hoses that insert into the boots four clamps on the intake boots gasket on passenger side intake manifold as I have to loosen it to remove ac compressor bolts to move it out of the way to get to the power steering line additional things that I did that can provide more clues: cleaned the throttle body with solvent and a brush (did I brake it?) cleaned all the plastic intake tubes connected and reconected the two electrical plugs into the throttle body I did not disconnected the battery at all during the process One thing I did also was trying to start it without the j-shaped plastic tube that goes from throttle body to aux air pump and of course it did not start, I forgot to install it and then I noticed it, then installed and it started right up but rough. I wiggled the intake manifold a lot when it was loose and perhaps I disconnected something else like injectors or? I visually can't find anything wrong with it. When running I sprayed a little engine starter on the probable sources of leaks and the idle does not change except when spraying close to the air box, which I assume is normal. The codes I'm getting with my cheap obd2 scanner are all missfires P1319 GENERAL MISSFIRE P1314 MISSFIRE CYL 2 P1316 MISSFIRE CYL 4 P1313 MISSFIRE CYL 1 Please note that I can not take it to a mechanic since I live up in the mountains in central mexico (I live here for half a year since I'm semi-retired) and mechanics hera are far away and do not know anything about porsches, lol. anyway... HELP!!!!

POST 2Original post

Misfires are typically electrical or timing related. Re-check the electrical connections that were disconnected/re-connected. Are you sure that nothing else electrical was disconnected or knocked loose (like a wire from the flywheel sensor or cam position sensor or something similar to that)?

POST 3 / ORIGINAL POSTEROriginal post

Quotes source post: 473446

Thanks, It is possible that I knocked sothing loose when I was working on it as snaking that ps line is a pita, where are the connectors for the cps or fs? Would the obd2 reader detect those being unpluged?

POST 4Original post

Take a look at the hoses that go to the throttle body from the AOS (air oil separator). I just had mine disintegrate when it was messed with. I think you are chasing a vacuum leak. The CPS is on the pass side of the engine and the car will not run if unplugged. The 99 has an idle stabilization vale on the side of the throttle body.

POST 5 / ORIGINAL POSTEROriginal post

Ok got it running great, the bad thing is that I do not know what was the problem but is running even better than before This is what I did in case is helpful to someone: Cleaned throttle body, idle control valve, and mass airflow sensor with the correct spray cleaner, all of them were very dirty specially the ICV. Performed an AOS bypass by plugging the port on the throttle body and connecting the AOS to the airbox to burn crankcase fumes as much as possible (this works in all my other cars and I do not get emissions inspection here and Im a republican so I don't care, lol) My guess is that it was a combinatios of things but mainly that plastic tube fron TB to AOS, that clip o ring system looked a bit tired, Anyway thanks for all the help

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