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AOS degradation?

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

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHAOS degradation?

Leading reported evidence

Replace "while we're in there"

Performed · outcome unconfirmed

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 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 recently had the AOS replaced "while we're in there".
Original post Read captured discussion
AOS degradation?

Frequently discussed work

Adjust /slightly retarded if the monitoring reveals

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
One of my tech sources has said that the AOS functionality is monitored by the ECU, and intake cam timing is adjusted/slightly retarded if the monitoring reveals that the "separation" of the air and oil is inadequate.
Original post Read captured discussion
AOS degradation?

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Leading evidence: 'Replace "while we're in there"' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Adjust /slightly retarded if the monitoring reveals' (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 · 4 captured posts examined · 0 partial discussions

Compare 3 other evidence results

Adjust /slightly retarded if the monitoring reveals

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
One of my tech sources has said that the AOS functionality is monitored by the ECU, and intake cam timing is adjusted/slightly retarded if the monitoring reveals that the "separation" of the air and oil is inadequate.
Original post Read captured discussion
AOS degradation?

Inspect diaphragm, you would probably discover a very small rip

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
If you dissected the old AOS to inspect the diaphragm, you would probably discover a very small rip.
Original post Read captured discussion
AOS degradation?

Replace /

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
Did you replace/reconnect any of the other AOS/vacuum hoses 'while you were in there' ?
Original post Read captured discussion
AOS degradation?

Frequently discussed actions (4)

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

Adjust /slightly retarded if the monitoring reveals

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
One of my tech sources has said that the AOS functionality is monitored by the ECU, and intake cam timing is adjusted/slightly retarded if the monitoring reveals that the "separation" of the air and oil is inadequate.
Original post Read captured discussion
AOS degradation?

Inspect diaphragm, you would probably discover a very small rip

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
If you dissected the old AOS to inspect the diaphragm, you would probably discover a very small rip.
Original post Read captured discussion
AOS degradation?

Replace "while we're in there"

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 recently had the AOS replaced "while we're in there".
Original post Read captured discussion
AOS degradation?

Replace /

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
Did you replace/reconnect any of the other AOS/vacuum hoses 'while you were in there' ?
Original post Read captured discussion
AOS degradation?

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: 20261026T155324Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

I recently had the AOS replaced "while we're in there". Now my beloved '99 runs discernibly better! Is the improvement my imagination or does AOS functionality degrade over time and adversely affect performance accordingly? FYI-the car has never "smoked"...still doesn't. relinuca

POST 2Original post

If you dissected the old AOS to inspect the diaphragm, you would probably discover a very small rip. The longer the rip, the more the AOS function is compromised. I posted some photos of a post mortem of an AOS cadaver that a fellow Forum member sent. Did you replace/reconnect any of the other AOS/vacuum hoses 'while you were in there' ?

POST 3Original post

Quotes source post: 13605262

"runs discernibly better" Better how? More power. Smoother at speed, at idle? Less rough, less noise? Please elaborate.

POST 4 / ORIGINAL POSTEROriginal post

All of the AOS hoses were still in good shape; hence, all were reused/reconnected. "Better"...how to describe. While I recognize such labels are highly subjective, I would further describe the improvement as the engine runs "smoother" in the 2K and higher RPM range, and it feels more responsive to tiny changes in "go pedal" pressure. One of my tech sources has said that the AOS functionality is monitored by the ECU, and intake cam timing is adjusted/slightly retarded if the monitoring reveals that the "separation" of the air and oil is inadequate. After all, the AOS is basically a pollution control system. This sounds logical to me, but I'm not sufficiently knowledgeable to conclude its true. Hence, my postings. relinuca

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