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1998 996 Replaced AOS and now it won't idle.

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

Discussion summary

YOUR RESEARCH1998 996 Replaced AOS and now it won't idle.

Leading reported evidence

Check function of the idle air valve

Performed · outcome unconfirmed

No successful repair reported for this finding.

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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 performed work without a confirmed outcome
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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.

Performed · outcome unconfirmed · Original poster

I've tried blocking a few of the vacuum hoses to eliminate them, and have cleaned and checked the function of the idle air valve that's attached to the throttle body.

1998 996 Replaced AOS and now it won't idle.
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Leading evidence: 'Check function of the idle air valve' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check function of the idle air valve' (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.

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1 matching discussions · 7 captured posts examined · 0 partial discussions

Compare 4 other evidence results

Replace aos and have gone

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 replaced my AOS and have gone for a drive to blow out the oil from the exhaust that made its way there when the AOS failed.

1998 996 Replaced AOS and now it won't idle.

Check on the new aos

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

I would start by doing a vacuum check on the new AOS.

1998 996 Replaced AOS and now it won't idle.

Check vacuum level at the oil fill cap

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

You need to check the vacuum level at the oil fill cap, it should not be more than 5 inches of water; any more than that and the AOS is bad.

1998 996 Replaced AOS and now it won't idle.

Replace hose

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

You might want to consider just replacing the hose with a new one.

1998 996 Replaced AOS and now it won't idle.
Frequently discussed actions (9)

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

Check function of the idle air valve

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've tried blocking a few of the vacuum hoses to eliminate them, and have cleaned and checked the function of the idle air valve that's attached to the throttle body.

1998 996 Replaced AOS and now it won't idle.

Check on the new aos

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

I would start by doing a vacuum check on the new AOS.

1998 996 Replaced AOS and now it won't idle.

Check vacuum level at the oil fill cap

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

You need to check the vacuum level at the oil fill cap, it should not be more than 5 inches of water; any more than that and the AOS is bad.

1998 996 Replaced AOS and now it won't idle.

Replace aos and have gone

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 replaced my AOS and have gone for a drive to blow out the oil from the exhaust that made its way there when the AOS failed.

1998 996 Replaced AOS and now it won't idle.

Replace hose

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

You might want to consider just replacing the hose with a new one.

1998 996 Replaced AOS and now it won't idle.

Replace plugs as they were massively oil fouled

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'm also going to try changing the plugs as they were massively oil fouled from when the AOS let go.

1998 996 Replaced AOS and now it won't idle.

Test there

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 could wedge the throttle open at a speed where it will self sustain, about 1500 rpm and try the cap test there.

1998 996 Replaced AOS and now it won't idle.

Use aftermarket aos, i, would almost bet

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 used an aftermarket AOS, I, would almost bet that is your issue; wwe have had zero luck with aftermarket AOS units.

1998 996 Replaced AOS and now it won't idle.

Use combination a pinch clamp and an o-ring, either of

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

It uses a combination a pinch clamp and an O-ring, either of which can become problematic with age.

1998 996 Replaced AOS and now it won't 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.

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

  • Pelican Parts: 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: 20261026T130754Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

I just replaced my AOS and have gone for a drive to blow out the oil from the exhaust that made its way there when the AOS failed. However the car just won't idle. It's not that it's a poor idle, it's that it simply won't idle at all. I've tried blocking a few of the vacuum hoses to eliminate them, and have cleaned and checked the function of the idle air valve that's attached to the throttle body. None of this has made any difference. Obviously I'm concerned that there is a massive air leak somewhere behind the throttle butterfly, but I'm not keen to go there until I've checked out everything else. I'm also going to try changing the plugs as they were massively oil fouled from when the AOS let go. If anyone has any ideas of what to look at next, I'm keen for your input. I guess what I'm asking is this: Is there an electrical cable/wire/connector somewhere that would cause the engine to die instantly at idle speed?

POST 2Original post

I would start by doing a vacuum check on the new AOS. We have seen new units that were duds right out of the box. You need to check the vacuum level at the oil fill cap, it should not be more than 5 inches of water; any more than that and the AOS is bad. If you used an aftermarket AOS, I, would almost bet that is your issue; wwe have had zero luck with aftermarket AOS units.

POST 3 / ORIGINAL POSTEROriginal post

The problem with that is that the car won't idle at all, so I can't leave it idling and then pop round to the back and look at the cap. I could wedge the throttle open at a speed where it will self sustain, about 1500 rpm and try the cap test there. I guess I could also just remove all the pipe connections to the inlet manifold/plenum and blank them off and see if it idles then.

POST 4 / ORIGINAL POSTEROriginal post

I just discovered that the hard hose from the AOS to the intake plenum had become disconnected at the AOS. It's a b1tch to get to but hopefully I can reconnect it in a way that will mean it stays reconnected. Time to pull the LH inlet manifold again..

POST 5Original post

You might want to consider just replacing the hose with a new one. It uses a combination a pinch clamp and an O-ring, either of which can become problematic with age. Be sure to apply a small amount of lubricant to where it attaches to the AOS, and it should seat with a click.

POST 6 / ORIGINAL POSTEROriginal post

Thanks - you're absolutely right, it took a lot of effort to push it on, but when 'home' it clicked, and I don't remember there being a click when I pushed it on the first time around. I've now got the inlet manifold back on but frustratingly, one of the very small bore plastic vacuum pipes that comes out of the back of the rubber hose that connects the plenum to the manifold has come out of the thing it's connected to somewhere in the rats nest near the starter motor.

POST 7Original post

Quotes source post: 9380612

You are now beginning to understand why we require "carte blanche" when we do one of these; any hose or connection that looks even questionable goes in favor of new pieces. Not the cheapest approach, but it prevents "come backs".

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