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2001 C4 Rough idle.

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

Discussion summary

YOUR RESEARCH2001 C4 Rough idle.

Reported or suspected cause

aos return line had cracked all

Reported cause

No successful repair reported for this finding.

1
Identified cause
0
Suspected cause
0
Reported fixes
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 identifying a cause
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.

Reported cause

Wasn't any of the easy fixes- we had to drop the engine and it turned out to be the AOS return line had cracked all to hell making for a very bad vacuum leak.

Original post Read captured discussion
2001 C4 Rough idle.
Frequently discussed work

Check any vacuum leaks

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 checked for any vacuum leaks, but haven�t found any so far.

Original post Read captured discussion
2001 C4 Rough idle.
Read full discussion summary

Leading evidence: 'aos return line had cracked all' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'aos return line had cracked all' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check any vacuum leaks' (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 · 6 captured posts examined · 0 partial discussions

Compare 4 other evidence results

Check any vacuum leaks

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 checked for any vacuum leaks, but haven�t found any so far.

Original post Read captured discussion
2001 C4 Rough idle.

Install maf the car won�t start at all just cranks

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've changed the MAF and still no luck, as matter of fact when I installed the MAF the car won�t start at all just cranks.

Original post Read captured discussion
2001 C4 Rough idle.

Replace fuel pump

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

Hey all, so let me start by saying, I�ve replaced the fuel pump, and replaced spark plugs, still that rough idle, like it�s accelerating then letting off type idle.

Original post Read captured discussion
2001 C4 Rough idle.

Replace maf and still no luck, as matter of fact

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've changed the MAF and still no luck, as matter of fact when I installed the MAF the car won�t start at all just cranks.

Original post Read captured discussion
2001 C4 Rough idle.
Frequently discussed actions (10)

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

Check any vacuum leaks

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 checked for any vacuum leaks, but haven�t found any so far.

Original post Read captured discussion
2001 C4 Rough idle.

Clean maf or purchase a new one

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

First thing to do though is as others have suggested- new filter, clean maf or purchase a new one, clean throttle body, replace spark plugs and coil packs.

Original post Read captured discussion
2001 C4 Rough idle.

Clean throttle body

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 cleaned your throttle body?

Original post Read captured discussion
2001 C4 Rough idle.

Suggestion

First thing to do though is as others have suggested- new filter, clean maf or purchase a new one, clean throttle body, replace spark plugs and coil packs.

Original post Read captured discussion
2001 C4 Rough idle.

Install maf the car won�t start at all just cranks

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 changed the MAF and still no luck, as matter of fact when I installed the MAF the car won�t start at all just cranks.

Original post Read captured discussion
2001 C4 Rough idle.

Replace fuel pump

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

Hey all, so let me start by saying, I�ve replaced the fuel pump, and replaced spark plugs, still that rough idle, like it�s accelerating then letting off type idle.

Original post Read captured discussion
2001 C4 Rough idle.

Replace ignition coils

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 test / replace the coil packs ?

Original post Read captured discussion
2001 C4 Rough idle.

Replace maf and still no luck, as matter of fact

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 changed the MAF and still no luck, as matter of fact when I installed the MAF the car won�t start at all just cranks.

Original post Read captured discussion
2001 C4 Rough idle.

Replace spark plugs and coil packs

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

First thing to do though is as others have suggested- new filter, clean maf or purchase a new one, clean throttle body, replace spark plugs and coil packs.

Original post Read captured discussion
2001 C4 Rough idle.

Replace spark plugs, still

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

Hey all, so let me start by saying, I�ve replaced the fuel pump, and replaced spark plugs, still that rough idle, like it�s accelerating then letting off type idle.

Original post Read captured discussion
2001 C4 Rough idle.

Test /

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 test / replace the coil packs ?

Original post Read captured discussion
2001 C4 Rough idle.
Reported and suspected causes (1)

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

aos return line had cracked all

No successful repair reported for this finding.

1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that report identifying a cause
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.

Reported cause

Wasn't any of the easy fixes- we had to drop the engine and it turned out to be the AOS return line had cracked all to hell making for a very bad vacuum leak.

Original post Read captured discussion
2001 C4 Rough 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.

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: 20261026T100758Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hey all, so let me start by saying, I�ve replaced the fuel pump, and replaced spark plugs, still that rough idle, like it�s accelerating then letting off type idle. Very unbalanced. I've changed the MAF and still no luck, as matter of fact when I installed the MAF the car won�t start at all just cranks. Starts without The MAF plugged in. i checked for any vacuum leaks, but haven�t found any so far. SO I am out of ideas.

POST 3 / ORIGINAL POSTEROriginal post

Quotes source post: 17266292

I thought of it, but I�m not sure if that�s going to be the legit problem... I�m so tired of throwing money at it. How can I know for sure?

POST 4Original post

Have you cleaned your throttle body? Check that all the intake boots / couplers are tight?

POST 5Original post

With what brand MAF did you replace ? If not OEM Bosch, you are in trouble...

POST 6Original post

It can be a number of things. sounds a lot like what I had wrong with mine when I bought it. Wasn't any of the easy fixes- we had to drop the engine and it turned out to be the AOS return line had cracked all to hell making for a very bad vacuum leak. That wasn't all either, it was also the Variocam solenoid not operating at times causing a continued rough idle. First thing to do though is as others have suggested- new filter, clean maf or purchase a new one, clean throttle body, replace spark plugs and coil packs. Then when that is done get that wallet out and give your Indy a call.

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