35 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHmisfire help needed
Reported or suspected cause
cause and in this case it was not
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
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Reported cause · Original poster
I normally keep parts until I am absolutely sure it was the cause and In this case it was not.
Leading evidence: 'cause and in this case it was not' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'cause and in this case it was not' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check code and i had #1 and #2 misfire' (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 report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Reported cause
when the fuel trim data is erased, then we can surmise that this issue is fuel-related.
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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Performed · outcome unconfirmed · Original poster
I stopped again, checked the code, same code, still 40 miles to home, so I cleared it again and the car ran fine.
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
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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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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
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Performed · outcome unconfirmed · Original poster
I uninstalled and installed the newest version and it won't open on two different computers.
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.
35 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.
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Generation: 20261026T212127Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Good day all,
I've been on the forum a while and help when I could, so now I need some assistance. I have a 2004 C2 manual Cabriolet with 98K miles. I don't drive it as much as I would like, but here is the scenario from this week. I drove the car on Saturday with no issues. I drove it again this morning to work with no issues. When I went to lunch, I was stopped at a traffic light and I was there for roughly a minute and I got a rough idle and a check engine light. When the light went green, I found a parking lot within a quarter mile and read the codes. i don't remember the exact code, but it was a #2 cylinder misfire I cleared it and the car ran fine back to the office.
After work (I'm 63 miles from home), so I started the car and no issues until I got to the same traffic light and had the same results.I pushed the gas pedal and at 1200 RPM's, the light went out, so I continued on my way home.
Since i had to travel thru a town, at the next light, the light returned, but this time it was flashing. I stopped again, checked the code, same code, still 40 miles to home, so I cleared it again and the car ran fine.
The next light, same thing, however, this time I pulled over to check the code and I had #1 and #2 misfire, with very rough idle. I waited five minutes, cleared the codes and continued home. The car ran like it never had an issue for the rest of the trip. If any one has any advise, I'm all ears. Previously, I had a small evap leak, smoke tested and fixed that. Then I had a large leak, I replaced the gas cap and fixed that. I've owned the car roughly 3 years and when I first purchased it, I replaced the plugs and the coil packs (with the 997 coils) and haven't have any engine issues other than what's listed here. Oil pressure was1.5 at idle and 2.5 at 60, water temp was at left side of 0.No leaks under car, no oil or fuel smells, no water in the oil or vice versa.
Thanks for any assistance.
Replaced the #2 coil last night, fired it up and it idled much more smoothly. I won't get a chance to take a drive for another day or two. But, hope this is the fix.
I replaced all but #6 a couple of years ago with the upgraded 997 coils. I had the one left over from #6, only because I could not get to it without taking the muffler or header off. I broke one bolt holding the header one, so I stopped there to limit any headaches I would create for myself.
I purchased the Beru coils, I think I got them from ECP Euro, but not sure since it's been a few years ago. I don't recall if the old coils had a manufacturer marking, but with the history of the car, I would think they were Porsche parts.
Had the chance to drive the car last week and the CEL did not come back on. I had to get an inspection on Friday and all went ok. Five miles from home, at a traffic light, the light returned. When I can make time, I will take it all back apart and replace the spark plug. I didn't have one on hand when I did this before. Will see how it goes.
Next time it misfires, restart the engine without clearing the trouble code. I want to see if it will still misfire.
When you clear the trouble code, you�re erasing/resetting the fuel trim data. If we can determine that the car stops misfiring
only
when the fuel trim data is erased, then we can surmise that this issue is fuel-related.
I've driven it after the CEL is on for a few miles. Initially, the light was flashing, then as I drove it would go solid, then go out completely, until the next traffic light. After the second, or third reset, the light stayed on constantly without flashing. The last time I cleared the code, I was on my way home from the inspection station. The light came on and stayed solid, no flashing and I was roughly 3 miles from home. I have not reset it since, nor have I made time to drive it. Busted my left knee again from an old injury and it's a 6 speed, so It may be a few more days.
i did feel it misfire. I basically had a rough idle. It sort of smoothes out once i was going, until number one also misfired. So far, number 1 hasn't misfired again. I have not reset it yet from the last fail, nor have i rechecked the codes. I may get to do that today.
Before you erase the trouble codes again, I would like to request you check the fuel trims in the data list. I�m starting to wonder whether there is an issue with a fuel injector in cylinder 2.
I hope you didn�t throw away the ignition coil you recently removed.
I may get an opportunity to check fuel trims today. I don't know if my Foxwell will do that, but I do have Durametric. I did not throw the coil I replaced out. I normally keep parts until I am absolutely sure it was the cause and In this case it was not. I will hang on to it, in case i need it in the future. I do appreciate your help and I will see what I can find for fuel trims. I'm not sure what the acronyms are for fuel trims, but I know it has been mentioned on this board a few times. I may have a book at home also that states what they are.
Good to hear about the coil.
Both your Foxwell and Durametric ought to be able to retrieve the fuel trim data. Here�s a good video by LN Engineering featuring Tony Callas� breakdown about fuel trims. He explains it in a way that�s very easy to understand.
You Tube
And you�re welcome� I feel bad about misreading your initial post and suggesting a coil replacement though - that�s on me.
Wouldn't you know as soon as I need the Durametric, It would load on my computer. I uninstalled and installed the newest version and it won't open on two different computers. Even plugged into the car. The Foxwell worked, but I got some strange events. First the car idled ok, then it had a rough idle. Still had P0302 pending, but I hadn't erased it. The CEL was on, but the rpm's would fluctuate a bit. When the rpm's went up, the light would stay on but when it went back down, I didn't record the numbers, I would get a beep and the light would flash again.
Short term fuel on bank 1 fluctuated between 0-15%. Air flow rate from MAF sensor was 6.6. Short term fuel trim bank 1 sensor 2, 99.2%. I'm sure there are other parameters to look at, but I haven't captured live data on the Foxwell before and was hoping the Durametric was going to be the ticket to capture what I needed. Let me know what live data to capture and I will give it another go with the Foxwell as I try to figure out why the Durametric no longer works for me. One more thing, even though the CEl was on, once I turned the car off, I looked for codes again and the Foxwell indicated the MIL was off and no codes . Hmmmm
Which Foxwell device do you have? Are you communicating with the car via the Porsche-specific software/protocol? Or did you connect using the universal/generic OBD2 option?
I have the Foxwell NT530 with the Porsche software loaded. It seems to have plenty of options to record, however, I did see fuel trims. I should time later today to explore more and see what options I need to record. I was thinking maybe the MAF sensor was going bad, but I think that would cause more issues other than #2 misfire.
tonight, the CEL is back on and I did not clear it. Still shows the #2 misfire. Rough idle, however, it seems like the car is trying to compensate since the idle will smooth for a few seconds, then I get a beep. That is fairly constant.
Parameters in checked:
Calculated load value: 2.7 -3.9%
Short term fuel trim Bank 1: stayed at 0%
Short term fuel trim Bank 2: stayed at 0%
Short term fuel trim Bank 1 Sensor 1: 0%
Short term fuel trim Bank 1 Sensor 2: 99.2%
short term fuel trim Bank 2 Sensor 1: 0%
Short term fuel trim Bank 2 Sensor 2: 99.2%
I've reached out locally to see if anyone has Durametric software that will load on their laptop. I would love to look at Cam deviations now.
Those values look like the trouble codes were erased immediately before the photo was taken. That�s really weird if the car had been running for 10 minutes.
code was still present and the light was still on along with rough idle. Something was making an adjustment since it would smooth out for a half a second or 2, then back to being rough, a beep letting me know the misfire had happened again. I looked at misfire also, and the other cylinders may have had one or two, but number 2 had 82.
Replaced the spark plug with same result, except it ran smoother for longer. I have not driven it (knee still recuperating) and I was afraid of doing damage to the engine. I may just have it hauled to the indy and let them diagnose it.
Update�-
finally had time to work on this. And replaced the injectors. While doing so, I broke the oil filler tube. One ear was broken already, but it done. Had to remove the alternator to fix it, what a PITA to get that back in. Anyway, 40 mile run today and no CEL and it ran much smoother. Thanks for all the help.
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