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911uk

Is that a dead cat?

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

Discussion summary

YOUR RESEARCHIs that a dead cat?

Leading reported evidence

Check temperature pre and post cat

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

I just checked the temperature pre and post cat on both banks ~230F (i.e.

Is that a dead cat?
Read full discussion summary

Leading evidence: 'Check temperature pre and post cat' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check temperature pre and post cat' (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 · 5 captured posts examined · 0 partial discussions

Compare 4 other evidence results

Replace aos went

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

AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?

Run cat

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

AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?

Clean though and re-mot a month later - no difference

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

AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?

Combined work: Replace aos went + Run cat

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
1
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 report an unsuccessful attempt
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.

Unsuccessful attempt · Original poster

I am running IPD plenum + BMC Air filter / high-flow 200 CELL cats / DMS Remap AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?
Frequently discussed actions (5)

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

Check temperature pre and post cat

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

I just checked the temperature pre and post cat on both banks ~230F (i.e.

Is that a dead cat?

Clean though and re-mot a month later - no difference

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

AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?

Combined work: Replace aos went + Run cat

No successful repair reported for this finding.

0
Reported fixes
1
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that report an unsuccessful attempt
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.

Unsuccessful attempt · Original poster

I am running IPD plenum + BMC Air filter / high-flow 200 CELL cats / DMS Remap AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?

Replace aos went

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

AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?

Run cat

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

AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

Is that a dead cat?
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.

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

  • 911uk: 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: 20261026T142254Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

My 2003 C4S @166k failed emission test - running rich! There are no engine faults or OBD2 codes Running rich at idle - post-sensor mirroring pre-sensor - is this a sign that CATs are not doing their job? I have plotted the o2 sensors (pre/post cat) reading from both banks. MAF reading and have tried to compare the data. Can anyone help?

POST 2 / ORIGINAL POSTEROriginal post

Just to add.... I am running IPD plenum + BMC Air filter / high-flow 200 CELL cats / DMS Remap AOS went and was replaced week before the initial MOT, ran cat-clean though and re-mot a month later - no difference to the emissions.

POST 3Original post

Both banks and pre cat lambda sensor is being mirrored by the post cat sensors. That indicates both cats are not working . There is normally a reason for 2 cats to fail though and thats a misfire or a rich mixture ie maf fault. The pre cat sensor switching looks pretty poor to me .. that may or may not be a fault as it might just be the scope thats slow .. It should look more like the attatched image although not quite that precise !

POST 4 / ORIGINAL POSTEROriginal post

Thanks for the response deMort I just checked the temperature pre and post cat on both banks ~230F (i.e. in and exit of the cat) - assume this also confirms the cat! I have order pair of Topgear Cats and the sensors/MAF are original so also ordered 4 sensors and MAF. Thanks for your help!

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