5 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH2004 996 C2 engine rattle
Leading reported evidence
Replace right side cat
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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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 haven't had any related engine codes, but I did have an intermittent p0430 code (catalyst system below efficiency) and I replaced the right side cat with an aftermarket unit after discovering element in the original was loose and banging around.
Leading evidence: 'Replace right side cat' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check dmf' (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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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
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Suggestion · Original poster
I tried to check the DMF- but I'm not sure I really knew what to expect.
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
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Suggestion
Did you check your DMF real good for looseness while doing the IMS/clutch?
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.
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Suggestion
I havent check my exhaust or heat shields yet but it doesnt seem like it's coming from there.
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.
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Suggestion · Original poster
I plan on bringing the car to a recommended indy mechanic when I get a chance, but I'm working out of town for at least the next week.
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.
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Performed · outcome unconfirmed · Original poster
I haven't had any related engine codes, but I did have an intermittent p0430 code (catalyst system below efficiency) and I replaced the right side cat with an aftermarket unit after discovering element in the original was loose and banging around.
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.
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: 20261026T152433Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hi everyone! I've been a lurker for a few months and have been using knowledge from the community to sort out my new to me 2004 996 C2with 90,000 miles. The car definitely had some deferred maintenance before I purchased it and I've been working through the common issues. So far I've replaced the AOS, IMS bearing (Pelican Parts bearing kit), RMS, water pump, thermostat, clutch, plugs and coils, motor mounts, and all fluids.
I've put about 1000 miles on it in the last 3 months, and 600 since completing the IMS and clutch. Somewhat recently I've noticed a bothersome engine rattle when at partial throttle. It happens in gear or not, at any speed, with engine rpms between about 2000-3500. I initially thought it might be a loose muffler or heat shield but I pulled them down to do the plugs and coils and snugged them up tight. The car doesn't smoke or burn any oil, and runs strong. The sound disappears at higher rpm and I don't hear it at idle. I'm not sure if it's related or not but I hooked my mityvac up to the connector at the intake manifold and discovered that there is a vacuum leak- so I'm preparing to do a complete replacement of the vacuum lines and components. I'd like input from you guys as to whether its worthwhile to change out the SAI valve while I'm in there. I haven't had any related engine codes, but I did have an intermittent p0430 code (catalyst system below efficiency) and I replaced the right side cat with an aftermarket unit after discovering element in the original was loose and banging around.
Do you have any ideas as to what my problem could be? I'm really hoping it isn't bore scoring..
Thanks!
Kevin
I tried to check the DMF- but I'm not sure I really knew what to expect. I could easily move the center part separately from the outer section- but it would spring all the way back to its original position on its own.
Edit: I reviewed the Bentley youtube video on DMF inspection. I believe mine is probably good.
Hi Kevin, I have a 03 c4s and have pretty much the same rattle that i hear at partial revs. I replaced the left cat (that was rattling) and did the ims (pelican), new clutch kit, AOS same as you so those arent the problem. I havent check my exhaust or heat shields yet but it doesnt seem like it's coming from there. I bring it into my mechanic shop this Friday. Will post what i find out from the shop. Let me know what you find as well?
Absolutely. I plan on bringing the car to a recommended indy mechanic when I get a chance, but I'm working out of town for at least the next week.
Does anyone think this might have something to do with the Variocam Plus system? I'm not getting any trouble codes, but it seems like the rpm range might be where the Variocam is kicking in.
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