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Idle speed fluctuation at stop

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8 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHIdle speed fluctuation at stop

Leading reported evidence

Run between 500-1000 rpm

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: 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
Usually wo fasteners on the mats it runs up the gas pedal and it only takes a slight touch of the edge of the mat to cause it to run between 500-1000 rpm.
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Idle speed fluctuation at stop

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Leading evidence: 'Run between 500-1000 rpm' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Run between 500-1000 rpm' (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 · 8 captured posts examined · 0 partial discussions

Frequently discussed actions (1)

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

Run between 500-1000 rpm

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
Usually wo fasteners on the mats it runs up the gas pedal and it only takes a slight touch of the edge of the mat to cause it to run between 500-1000 rpm.
Original post Read captured discussion
Idle speed fluctuation at stop

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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.

8 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: 20261026T152433Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

My 01 C4 Cab has started idling funny. When I am in neutral at a stop the engine revs upto close to 1000 rpm and back down to 500 rpm and up and down and up and down. Anyone know what might be the problem. Thanks

POST 2Original post

Could be the porsche mats moving up on the gas pedal especially when the mats arent fastened. I had that happen to me and the mats caused the idle to move from 500-1000 rpm like u said. Hope that is the case with u. take care '99 996 coupe red/black

POST 3 / ORIGINAL POSTEROriginal post

No just went to the garage and checked it out the mats are fine definitely seems to be engine or computer related. Its very up and down 500 to 1000 to 500 to 1000 back and forth like i was doing it my self

POST 4Original post

they all do that.. I have a 99 especially after hard driving.. the GT3 does it too....

POST 5Original post

500 rpm fluctuation certainly doesn't seem "normal" to me. Mine sure doesn't do that and I've never been in one that did.

POST 6Original post

Best thing is to have it checked out by the dealer or your mechanic but maybe u may want to try driving the car without the mats and see if the problem still occurs. Usually wo fasteners on the mats it runs up the gas pedal and it only takes a slight touch of the edge of the mat to cause it to run between 500-1000 rpm. take care.

POST 7Original post

I experienced the same thing on my '99 C2 especially when coming to a stop after driving in hot weather or when the AC is on. I have a feeling its intended to assist the radiator since often times the radiator fans also go on under such conditions.

POST 8Original post

Have the same problem but only when the AC is off.

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