6 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHSpark plug diagnostic assistance..
Leading reported evidence
Replace so both plugs and coils
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
1
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Leading evidence: 'Replace so both plugs and coils' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'coils are past their prime' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace coils based' (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.
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Performed · outcome unconfirmed
But after the marked improvement from the new coils in the Turbo engine next time the Boxster is in for plugs I'll have the coils replaced too.
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Discussions that suspect a cause
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Suspected cause
Even with no misfires I suspect the coils are past their prime.
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Discussions that contain suggestions
1
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Suggestion
I see no need to replace coils based on your pics.
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
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Generation: 20261026T165820Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
So I was motivated by the other plug change post and did mine tonight. Curious on thoughts regarding the old ones that came out. Car is a 99 3.4l 144k on car, unknown on this set of plugs. I did have 1 coil bolt that stripped and had to dremel a slot in the head to remove.
Plugs from cylinders 1-3
1-3 overhead
4-6
4-6 overhead
1-6
\"Modified" coil bolt
#4 and #5 look to be much older plugs then the other ones. They show a significant amount of wear compared to the other ones. The other ones look normal for wear.
Do yourself a great favor and get the newer upgraded coils. They come with revised bolts that make changing coils/plugs a much simpler job. The newer bolts are not recessed on the coil and stick out so you can get a normal wrench on them instead of fiddling with the recessed female bolts. Just saying, while you're in there......
Pretty hard to tell from you pic (flash) if there is much difference between them. If you are not showing misfire counts in the DME, replace with new plugs and carry on. I see no need to replace coils based on your pics. The good news is that they appear to be free of oil deposits.
Cheers
Thanks for the replies and input. My only concern was the difference in appearance on 4 and 5. May be hard to see in the photos. Both of them, and more so on #4, appeared to have accelerated wear with some whitish deposits in #4. Just got the car about a month ago and trying to get everything baselined.
Replace the coils. Even with no misfires I suspect the coils are past their prime.
At 140K miles I had the plugs and coils replaced in my 996 Turbo. There was a cold start misfire that I thought new coils might address. (The tech suspects some lazy injectors. The coils are easier to get to than the injectors.)
The engine never misfires at any other times I might add and it doesn't misfire at cold start if I do not let the engine idle for more than a few seconds before easing the car out and getting underway.
The tech said the plugs should be replaced even though they had around 10K miles left to go before they were due. While I'm not usually a fan of premature plug changes the tech make good sensor. No way I wanted to nearly duplicate the cost of the new coils in another 10K miles to have the plugs replaced.
So both plugs and coils were replaced. Of course, the old coils looked ok.
Even so, afterwards the engine ran better. I've had the plugs replaced -- on miles -- several times before so I attribute the improved engine performance to the new coils.
The cold start/idle misfires were still present with the new coils. (Unless this misfire appears at other times those lazy injectors are going to be remain in service a long long time.)
You can of course nurse the coils along if you want. I've nursed the coils in my 2002 Boxster now for over 315K miles. (And I guess I'm guilty of nursing the injectors in my Turbo too, now.)
But after the marked improvement from the new coils in the Turbo engine next time the Boxster is in for plugs I'll have the coils replaced too.
Tan or light brown in color is okay. The white deposits on #4 and 5 indicate the plug(s) was burning too hot, probably because the gap is so large. I'll second the suggestion to replace all the plugs and coils. The newer updated coils are better and the new style coil bolts are very simple to install and snug up.
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