Rennlist

Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

Add to repair workspace

New repair projectOpen repair workspace

Original source

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

THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHMisfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

Leading reported evidence

Clean � no visible cracking, carbon tracking, or fouling

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
I pulled the spark plugs and ignition coils and they all looked clean � no visible cracking, carbon tracking, or fouling.
Original post Read captured discussion
Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

Read full discussion summary

Leading evidence: 'Clean � no visible cracking, carbon tracking, or fouling' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Clean � no visible cracking, carbon tracking, or fouling' (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 · 2 captured posts examined · 0 partial discussions

Compare 2 other evidence results

Replace mass air flow sensor

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
on the missfire on all 6 cylinders check or replace the MAF Sensor with a known good one or do much more specific testing on it...
Original post Read captured discussion
Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

Test on it

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
on the missfire on all 6 cylinders check or replace the MAF Sensor with a known good one or do much more specific testing on it...
Original post Read captured discussion
Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

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.

Clean � no visible cracking, carbon tracking, or fouling

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 pulled the spark plugs and ignition coils and they all looked clean � no visible cracking, carbon tracking, or fouling.
Original post Read captured discussion
Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

Replace mass air flow sensor

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
on the missfire on all 6 cylinders check or replace the MAF Sensor with a known good one or do much more specific testing on it...
Original post Read captured discussion
Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

Test on it

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
on the missfire on all 6 cylinders check or replace the MAF Sensor with a known good one or do much more specific testing on it...
Original post Read captured discussion
Misfire in All 6 Cylinders ? Vacuum Leak from Intake Hose?

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.

2 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: 20261026T112012Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hey everyone, I�m troubleshooting a persistent check engine light on my 2002 911 Carrera (996 Cabriolet). The codes I�m getting are for misfires on all six cylinders (P0300�P0306). I pulled the spark plugs and ignition coils and they all looked clean � no visible cracking, carbon tracking, or fouling. To dig deeper, I had a smoke test done, and I think I found the culprit. There's visible smoke leaking from the central vacuum port on the intake manifold hose (P/N 996.110.120.53 � the accordion-style hose that connects the MAF to the throttle body). I'm linking a short video showing the exact leak spot below. I'm wondering: Has anyone else had this part fail in a similar way? Could a vacuum leak at this specific spot realistically cause misfires across all six cylinders ? Is replacing this part straightforward? Appreciate any insight or advice. Just trying to rule this in or out before throwing money at coils I may not need. Thanks in advance!

POST 2Original post

Yes that leak is common.... No, I don't think it is causing misfires on all 6 cylinders.. You can search the archive for the threads that show how to simply fix this leak with a plastic cap and gives the source for the cap...No need to even R&R the tupe... on the missfire on all 6 cylinders check or replace the MAF Sensor with a known good one or do much more specific testing on it...

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