Planet-9

High Surging Idle at Normal Engine Temp

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5 captured repliesPartial discussion capture · Source accounts, not a confirmed diagnosis

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YOUR RESEARCHHigh Surging Idle at Normal Engine Temp

Leading reported evidence

Use carb cleaner

Performed · outcome unconfirmed

No successful repair reported for this finding.

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Unsuccessful attempts: 1
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Discussions that performed work without a confirmed outcome: 1

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Performed · outcome unconfirmed
There are a few methods to find a vacuum leak, but I've always (carefully on a COLD engine) used carb cleaner to locate the vacuum leak.
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High Surging Idle at Normal Engine Temp

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Leading evidence: 'Use carb cleaner' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Use carb cleaner' (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.

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

Frequently discussed actions (1)

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Use carb cleaner

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

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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
There are a few methods to find a vacuum leak, but I've always (carefully on a COLD engine) used carb cleaner to locate the vacuum leak.
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High Surging Idle at Normal Engine Temp

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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.

Planet-9: 1 discussions

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I erased all codes anyway, and no change.
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Generation: 20261027T005001Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1Original post

Hi Guys - 2007 Cayman with 92k miles, and just this week, while stopped at lights, the engine will go from idle (+-700 rpms) and increase up to 1,600 rpms, then fall back down to 700, then go back up, or stay up around 1,600 until I hit blip the throttle. Temp gauge appears to be operating normal, and this is happening well after the car is warmed up. Durametric Enthusiast Version showed no codes. I erased all codes anyway, and no change. Any idea what's causing this? Thanks!

POST 2Original post

It usually indicates a vacuum leak some where. There are a few methods to find a vacuum leak, but I've always (carefully on a COLD engine) used carb cleaner to locate the vacuum leak. Hopefully others will chime in, but that'd be my guess. **I realize there are quite a few possibilities for a surging idle (i.e.: PCV needing replacement, TPS, plugs, etc...). I just mention a vacuum leak because that always seemed to be the most common issue with my previous (non- Porsche ) cars.

POST 3Original post

Owen, there is a vacuum diagram on the engine cover. Fortunately there are not many vacuum lines on this engine so if that is the problem hopefully it will be easy to locate. There is one going to the scavenge pump on the front of the engine on cylinders 4-6; two connections under the intake runners; one that goes to the throttle body; one that goes to the resonance flap. There may be one more but I think that is all of them. The diagram is somewhat hard to read but some of them cross over to each other (intake runners) and there is a 3 way T connection as well. Hope this helps.

POST 4Original post

Well.... Started it up after work, larger cloud of smoke than normal, but not too much more... Started driving home on the George Bush, and I see smoke from the back (same color as the random startup smoke) during traffic start/go. Wonder if it's a concern enough to be able to make it home, and then it starts getting REALLY bad, smoking up all lanes..... Pull off and the engine dies, push in the clutch and coast into a WalMart parking lot (that was lucky). Engine won't turn over. Towed it to a local shop - they think it's the AOS, and maybe seized due to oil in the cylinder. They don't think it's catastrophic, but they have seen one that was... Good thoughts my way please!

POST 5Original post

Horrible ending, sorry to hear! Hopefully it all works out in the end.

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