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Porsche Forum Australia

Rough Idle

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Original source
6 captured repliesPartial discussion capture · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHRough Idle

Leading reported evidence

Install x51 headers

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

Also did an ECU tune and installed X51 headers.

Original post Read captured discussion
Rough Idle
Read full discussion summary

Leading evidence: 'Install x51 headers' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Install x51 headers' (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 · 6 captured posts examined · 1 partial discussions

Compare 2 other evidence results

Replace about a month ago(the dme was

Suggestion or failed attempt

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 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

Hey guys recently after major service the car suffered from a faulty AFM, this was replaced about a month ago(the DME was reset, battery taken out for 35mins) after that the car runs really rough idle, the rpms fluctuate between and i am not joking between 200-600rpm, the idle at warm up should be 600 i presume however even when i am driving around at about 1200rpm the engine hesitates to accelerate and just fluctuates between 1200-1500 like a sine wave.The correct AFM was installed.

Original post Read captured discussion
Rough Idle

Reset battery taken out

Suggestion or failed attempt

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 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

Hey guys recently after major service the car suffered from a faulty AFM, this was replaced about a month ago(the DME was reset, battery taken out for 35mins) after that the car runs really rough idle, the rpms fluctuate between and i am not joking between 200-600rpm, the idle at warm up should be 600 i presume however even when i am driving around at about 1200rpm the engine hesitates to accelerate and just fluctuates between 1200-1500 like a sine wave.The correct AFM was installed.

Original post Read captured discussion
Rough Idle
Frequently discussed actions (3)

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

Install x51 headers

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

Also did an ECU tune and installed X51 headers.

Original post Read captured discussion
Rough Idle

Replace about a month ago(the dme was

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

Hey guys recently after major service the car suffered from a faulty AFM, this was replaced about a month ago(the DME was reset, battery taken out for 35mins) after that the car runs really rough idle, the rpms fluctuate between and i am not joking between 200-600rpm, the idle at warm up should be 600 i presume however even when i am driving around at about 1200rpm the engine hesitates to accelerate and just fluctuates between 1200-1500 like a sine wave.The correct AFM was installed.

Original post Read captured discussion
Rough Idle

Reset battery taken out

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

Hey guys recently after major service the car suffered from a faulty AFM, this was replaced about a month ago(the DME was reset, battery taken out for 35mins) after that the car runs really rough idle, the rpms fluctuate between and i am not joking between 200-600rpm, the idle at warm up should be 600 i presume however even when i am driving around at about 1200rpm the engine hesitates to accelerate and just fluctuates between 1200-1500 like a sine wave.The correct AFM was installed.

Original post Read captured discussion
Rough Idle
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.

6 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Porsche Forum Australia: 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: 20261026T113718Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hey guys recently after major service the car suffered from a faulty AFM, this was replaced about a month ago(the DME was reset, battery taken out for 35mins) after that the car runs really rough idle, the rpms fluctuate between and i am not joking between 200-600rpm, the idle at warm up should be 600 i presume however even when i am driving around at about 1200rpm the engine hesitates to accelerate and just fluctuates between 1200-1500 like a sine wave.The correct AFM was installed. any help would be great, Bottom end power is awful, however top end power is great, it's like turbo lag without the turbo, like Vtec. BTW car is a 98 C2 3.4L

POST 2Original post

Idle air control valve...... then again I have no idea if your car has one or it could be your TPS. That's all the help I have from your posted symptoms.

POST 3Original post

+1 ICV would be one of the first things to look at. Off chance O2 sensor and it won't be the forst time a new MAF is bad!!

POST 4 / ORIGINAL POSTEROriginal post

i forgot to mention i have Cat Bypass Pipes and O2 spacers. i'll remove the spacers tomorrow night as i am getting the car tuned the day after.

POST 5 / ORIGINAL POSTEROriginal post

Took out the O2 spacers. Car idles much better. And drives a lot smoother. Turns out you don't need O2 spacers on 3.4L. Also did an ECU tune and installed X51 headers. Drives a lot better in the lower rpms and a bit better on the top end.

This is a source reference. Confirm exact model applicability in the original material.