Rennlist

2002 996 C2 Misfire

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

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCH2002 996 C2 Misfire

Leading reported evidence

Use replacement

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
motor went bad (cracked head) so I was able to locate and purchase a good used replacement from a 2002 C4S, with a full Stainless exhaust.
Original post Read captured discussion
2002 996 C2 Misfire

Frequently discussed work

Run live data

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
I went ahead and hooked my scanner up and found at idle I had active misfires from cylinders 1,2,3 when running live data.
Original post Read captured discussion
2002 996 C2 Misfire

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Leading evidence: 'Use replacement' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Run live data' (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 · 4 captured posts examined · 0 partial discussions

Compare 1 other evidence results

Run live data

Suggestion or failed attempt

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
I went ahead and hooked my scanner up and found at idle I had active misfires from cylinders 1,2,3 when running live data.
Original post Read captured discussion
2002 996 C2 Misfire

Frequently discussed actions (2)

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

Run live data

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
I went ahead and hooked my scanner up and found at idle I had active misfires from cylinders 1,2,3 when running live data.
Original post Read captured discussion
2002 996 C2 Misfire

Use replacement

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
motor went bad (cracked head) so I was able to locate and purchase a good used replacement from a 2002 C4S, with a full Stainless exhaust.
Original post Read captured discussion
2002 996 C2 Misfire

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.

4 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: 20261027T070717Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

OK need some help here. I have a 2002 C2. motor went bad (cracked head) so I was able to locate and purchase a good used replacement from a 2002 C4S, with a full Stainless exhaust. When I did the engine swap I did the normal maintenance stuff while the engine was out, Oil/water separator, oil cooler, plugs, new IMS, RMS and so on. I did order a new spec clutch and a lightened flywheel. Got everything in the car and running. Started right up ran great, but a day later developed rough idle and a miss, but only at idle. It runs perfect above idea. now the car did sit for a couple years before I purchased it so I'm suspecting bad gas. The gas gauge was showing about a 1/16 of a tank. I went ahead and put in 8 gals of good premium gas along with some octane boost and BG fuel Additive. I ran it again and at idea I have still have the misfire after about 20 miles of running it. I went ahead and hooked my scanner up and found at idle I had active misfires from cylinders 1,2,3 when running live data. Then when I bring the car up from idle to about 2000 RPM's or so, all misfires drop off completely. This is what I'm suspecting. At idea the crank sensor or other sensor is sending back reading to the ECU outside of the parameters, caused by the lightened flywheel at idle, causing the misfires. Could this be the case? Has anyone experienced this? Could the lightened flywheel at idle be causing this. If that's the case would a turn on a Dyno solve this? Any suggestion would be appreciated... Again I'm only getting these misfires at idle, when I'm driving It's great. I have the live date to support this.

POST 2Original post

No, not that. More probable is an air leak that shows itself once the warm-up enrichment has tapered off. Do a smoke test.

POST 3Original post

Or a bad fuel injector.

POST 4Original post

If you're able to read it out, I'd assume you'd be able to measure fuel trims too? I'd do that and see what they are. False air is typically spotted via high/rich trims, and leaky injectors via lower trims. The work from there.

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