8 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHBank 1 misfires
Leading reported evidence
Test cam deviations
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
Tested the cam deviations and that was 0 and steady but Actual cam angle was all over the place although engine was cold and I had to rev it to prevent it stalling.
Leading evidence: 'Test cam deviations' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace coil packs as i have a spare' (1 discussions). For that action, 0 discussions report a resolution and 1 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 report an unsuccessful attempt
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Unsuccessful attempt · Original poster
Today I changed coil packs as I have a spare set and no change.
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
Tested the cam deviations and that was 0 and steady but Actual cam angle was all over the place although engine was cold and I had to rev it to prevent it stalling.
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.
8 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
911uk: 1 discussions
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Generation: 20261026T152433Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Was out driving yesterday and when I gave my 996.1 some beans at 6000rpm it lost all power and started backfiring. Luckily I was only 200 yards from home so limped her back.
Put the code reader on and got PO300, PO301,PO302,PO303 so whole bank 1 misfiring. It now won't idle and sounds really rough.
Today I changed coil packs as I have a spare set and no change. Spark plugs are new.
Tested the cam deviations and that was 0 and steady but Actual cam angle was all over the place although engine was cold and I had to rev it to prevent it stalling.
I suppose with it being whole of bank 1 and no mis fire on bank 2 that should rule out maf or AOS.
If it has jumped timing or the cam actuator has failed surely that would throw a code but only codes were the misfires.
Not sure what else to look at.
Does anyone have any idea before I need to take it to a Indie.
Cheers
The Engine was stripped down and was rebuilt by Hartech back in 2013 due to a faulty cracked head and all chains and guides were changed. Car only done 30k since so unlikely it's chain guides.
Yes car had been driven for at least 30 mins. Since posting i have done compression and leakdown and results were zero compression on cyl 1 and 100% leakdown on cylinder 1 and was coming out of the throttle body so presuming it's a intake valve not closing. Looks like i need to take cam cover off and see what's happening.
I had a go at answering on your other identical thread, I answered as though you had a problem with the whole bank as you had misfires logged for all three cylinders, I also mentioned about having a durametric, and as it has a missfire counter function you'd probably have been able to see it was just one cylinder, or mainly one cylinder. Sometimes a missfire on one cylinder can show up on other cylinders!
I'd buy a cheap boroscope and have a look in the cylinders with that, I think that would reveal more than removing the cam cover, and it is easier too.
Yes got misfires on cyl 1 2 and 3 but seems to be stemming from cyl 1. I have scoped the bore and seems like some light contact but could be just the light. My thoughts are it's either a valve seat come loose or a collapsed Lifter or damaged spring. Hence why I think cover needs to come off.
Some cheap boroscopes can look backwards towards the valves too, but yes you're at the point where cam cover needs to come off. At least there's no major damage to the piston head which is a positive!
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