12 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHNo power over 6.000 rpm (camshaft dev...)
Leading reported evidence
Check cam deviation (-1,11 position 1 and -7,28 position 2)
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
There was a 637 fault code (valve lift control checksum error) and 627 (valve lift control cylinder 1), misfires on one bank (4-6), checked the cam deviation (-1,11 position 1 and -7,28 position 2).
Leading evidence: 'Check cam deviation (-1,11 position 1 and -7,28 position 2)' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check cam deviation (-1,11 position 1 and -7,28 position 2)' (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.
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
We replaced the tensioners and the deviation dropped to -0,48 on position 1 and -6,55 on position 2, the valve fault codes don't come on anymore, the misfire number also dropped.
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
Personally, I would check for cylinder bore scoring on bank#2 before I'd dump anymore money into this engine.
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
To change 1 injector you have to pull a fair amount of parts, by the time you're there getting the other intake out is just not that big of a deal.
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
My mechanic thinks these are two separate problems and wants to change an injector on one cylinder.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Check cam deviation (-1,11 position 1 and -7,28 position 2)
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
There was a 637 fault code (valve lift control checksum error) and 627 (valve lift control cylinder 1), misfires on one bank (4-6), checked the cam deviation (-1,11 position 1 and -7,28 position 2).
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
We replaced the tensioners and the deviation dropped to -0,48 on position 1 and -6,55 on position 2, the valve fault codes don't come on anymore, the misfire number also dropped.
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.
12 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: 20261026T165820Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hi everybody!
So my 4S looses power a little over 6.000 rpm with an occasional judder, accompanied by a little puff of white smoke (noticed from another car). The engine light comes on for about 10 seconds.
There was a 637 fault code (valve lift control checksum error) and 627 (valve lift control cylinder 1), misfires on one bank (4-6), checked the cam deviation (-1,11 position 1 and -7,28 position 2). We replaced the tensioners and the deviation dropped to -0,48 on position 1 and -6,55 on position 2, the valve fault codes don't come on anymore, the misfire number also dropped.
So where do I go from here? My mechanic thinks these are two separate problems and wants to change an injector on one cylinder. What about the camshaft dev? Change the pads on one side? It's a bit frustrating because I had the engine out last year immediately when I bought the car and my mechanic and I failed to notice the issue beforehand (he works with 911's but is not a proper Porsche specialist).
I know this is something that has been talked about a lot on this forum already, but anyway, I'd like to engage a bit and maybe get to know a bit more about my car in the process
. Many thanks for the answers!
I personally would change all 6 injectors or they are all the same age and generally injectors have pretty even wear.
You could also have bad coils (Again age related)
To change 1 injector you have to pull a fair amount of parts, by the time you're there getting the other intake out is just not that big of a deal.
basically the labor is where the money is at, LN engineering sells the injectors, there is no free lunch on 996 injectors.. Pay to play..
There are multiple tasks that are enough work to start that the "while your there" can make sense for the long game.
One of the good reasons to run top end lube like Techron/Seafoam at least once between oil changes.. Helps keep the injectors free and clean.
So, time to finally solve this problem. Just did a short drive with the OBD connected again. The misfires happened under full acceleration in second gear, and only on one cylinder this time. No misfires when accelerating slowly or just revving stationary to 7000 rpm.
I'm starting to think this is not only camshaft deviation related (7,14 on one side and 1,11 on the other today). The coils are fairly new, so this leaves me with the injectors.
I'd also check to see what engine mounts and transmission mounts it has. There are reports that some of the stiff mounts cause misfire codes and pulled timing.
THE source for said reports is a post by Jake Raby
https://rennlist.com/forums/996-forum/1258842-i-hope-nobody-had-stock-in-aftermarket-engine-mounts.html
You might try pulling your O2 sensors and bore scoping your cats. I've seen this before where the cats had broken up and caused too much back pressure at higher RPMs for the car to accelerate.
This is a source reference. Confirm exact model applicability in the original material.
