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Boxster 2000, sudden Multiple Cylinder Missfires

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I have purchased my first Porsche Boxster and happy in general until recently.

Yesterday, out of the sudden, I noticed the car was missfiring after taking off from a stop light. It was rattling in low revs at the beggining, then at iddling as well. The check engine light started blinking, and a minute after it turn on solid orange color. I didn't drive the car more than 5 minutes until I found a Porsche Mechanic in the area. When the mechanic checked the car, the system diagnosed multiple missfires in all cylinders but #5. That raised my concerns, since I thought it was not normal to have all cylinders missfiring suddenly, at once. The mechanic asked me about the history of the car, and I told him that I have recently purchased it, and drove it around for 3 months/ 8000 Mi, with no issues whatsoever. I have only changed the oil about 400 miles ago, at 7000 Mi as directed. It had Mobil 1 synthetic, don't know the grade, but replaced it with Mobil 1 10W-30. considering this grade would work better with the hot summer in paso Robles, where i live (temps are average 100-110F at this time of the year). I have changed the oil filter as well, and only thing I know is that the car needed a service for Spark plugs and coils at 140,000. The odometer reads now 140,500 and I was about to take it to a Porsche Mechanic soon. So I thought this would be the problem, but just got a call from SGS Independent Porsche Service in SLO and they haven't been able to fix the issue. They took one spark plug off and the ignition coil to inspect. The y have found the plug was worn out but still working well aparently, the coil showed carbon deposit but again, in working condition. That is all I know about my car and today is Saturday so the shop is closed until Monday. I decided to sign up here, and post my experience and share with the forum, hoping this will help myself and others.

I do not know the Mechanic and I am not sure if they will try to reap me off with the repairs. I am not from around here, and I have been ripped off before, so...

A word of advise would be highly appreciated.


Thank you for the attention and interest in advance.


"He, whom burnt himself with milk, when he sees a cow, cries"




last edit: the car was running on reserve gas, I forgot to mention. One of the mechanics performing the computer diagnose, advised me to go put some gas, which i did immediately, then I returned the car on their lunch time, drpped keys on mailbox and left home. I was reaserching on the forum that the computer on car may need a few minutes running to get all the new data, and thought maybe this could solve the cars issue. Then the shop would charge a few extra hour for the labor. Not trying to sound paranoid, buy hey....it is a jungle out there!

Any clues/advise/thoughts?




Edited by GingkoBelover
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0W-40 or 0W-50 are Porsche recommended oils depending on your local climate.

Where I live it is common to have several days (in a row) over 100 degrees F -- I have always still used 0W-40 with no issues.

More important is to keep those (leaf and debris catching) radiators clean. The kind of cleaning where you remove the front bumper (covered here even in video) and clean the hard to get to places.


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I believe the issue is related simply to a fuel supply interruption - sloshing effect of a low fuel level upon acceleration away from lights.


On a side note, you really should change the oil back to that recommended by Porsche.



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SGS has a good reputation on the net. You can burn out the fuel pump running the gas level in the tank too low. You can also start to pick up debris, clog a fuel filter, clog the injectors. I'm sure they will check the fuel system. Be sure and tell then of the run low on gas incident to help their diagnosis focus on the problem area and reduce the time you pay for their diagnosis.

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Thank you for your reply. The already know I was running on reserve fuel. I did fill up the tank before dfroping the keys back to the shop. I hope this could solve the issue.

We'll see what do they find on Monday.

Thank you for your valuable comment.



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I wanted to post this update on my Boxster.

I posted the ad to sell the car and many people showed up to see it.

Somebody assessed the issue and came back to tell me that the problem is a broken spring valve.

I haven't decided what to do about this and torn between selling the car or take it to the shop and repair it.



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Something doesn't add up to me. You said the shop said the spark plugs were worn and there was carbon deposit on the coils and yet they didn't even recommend replacing those first? You also said the car needed the coils and spark plugs 500 miles ago so I assume those were not replaced at the time?

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They said the spark plugs were worn but STILL IN WORKING CONDITION. Same with the coils, they showed carbon deposit but once tested, they seemed to work as well.

I was about to take my car to the shop to perform the required scheduled maintenance.


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