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Po1371 and misfires after replacing cats

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

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YOUR RESEARCHPo1371 and misfires after replacing cats

Leading reported evidence

Replace cats

Performed · outcome unconfirmed

No successful repair reported for this finding.

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Unsuccessful attempts
1
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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.

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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

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Performed · outcome unconfirmed · Original poster

Replaced both cats on my 04 996 4S today.

Original post Read captured discussion
Po1371 and misfires after replacing cats
Frequently discussed work

Check pre and post cat o2 sensors

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Discussions that contain suggestions
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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

Have you checked your pre and post cat O2 sensors for both banks?

Original post Read captured discussion
Po1371 and misfires after replacing cats
Read full discussion summary

Leading evidence: 'Replace cats' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check pre and post cat o2 sensors' (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 · 6 captured posts examined · 0 partial discussions

Compare 2 other evidence results

Check pre and post cat o2 sensors

Suggestion or failed attempt

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Reported fixes
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Unsuccessful attempts
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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

Have you checked your pre and post cat O2 sensors for both banks?

Original post Read captured discussion
Po1371 and misfires after replacing cats

Run like trash

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

came to a stop and it starting running like trash.

Original post Read captured discussion
Po1371 and misfires after replacing cats
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.

Check pre and post cat o2 sensors

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

Have you checked your pre and post cat O2 sensors for both banks?

Original post Read captured discussion
Po1371 and misfires after replacing cats

Replace cats

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

Replaced both cats on my 04 996 4S today.

Original post Read captured discussion
Po1371 and misfires after replacing cats

Run like trash

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

came to a stop and it starting running like trash.

Original post Read captured discussion
Po1371 and misfires after replacing cats
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.

  • 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: 20261027T075545Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi all Replaced both cats on my 04 996 4S today. rattle in the old cat and found it was OEM and the other was aftermarket. Btw - no codes with old cats. Got everything in today fired her up and drove a bit. came to a stop and it starting running like trash. Pulled over and pulled codes. Got po 1371 and a bunch of misfires. Cleared then limped her home and started researching. I'm.wondering if i buggered up a solenoid bracket wrestling the new cats in there? Anyone seen this happen? Here's the link to what i found. https://rennlist.com/forums/996-turbo-forum/930334-valve-lift-control-fault.html Thanks in advance. David

POST 3 / ORIGINAL POSTEROriginal post

Quotes source post: 16912389

Solenoid wiring?

POST 4Original post

Quotes source post: 16912393

That would be my guess. It's basically right there. No issue prior; issue afterward. Should be easy to spot. Start simple: is it plugged in?

POST 5 / ORIGINAL POSTEROriginal post

Quotes source post: 16912532

In trying to trace the wires from tge solenoids back.. it didn't even look like they come close to the cats. Thanks for any advice.

POST 6Original post

Quotes source post: 16914120

Have you checked your pre and post cat O2 sensors for both banks? What scan tool are you using? Anything like a PIWIS or Durametric?

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