CEL at start up question

Started my 2007 Boxster S ~16,000mi for a sunny day, top down drive on Saturday. Upon engine starting up, check engine light is flashing and the engine is running quite rough. This goes on for what I guess to be 15-20 seconds, then engine began to run normally and the CEL went off completely. I never turned the engine off, went for 60 mile trip with a few stops and engine runs great as usual.This same scenario happened when the car was maybe a year old, except the CEL stopped flashing but stayed lite. Since car was under warranty I took it to the dealer and it was diagnosed as a misfire on a cylinder whose number I don't remember and that it was no big deal. I am curious to know if anyone has any thoughts as to what this might be and if it could be the precursor of something more serious.

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oldhoo07s
Started my 2007 Boxster S ~16,000mi for a sunny day, top down drive on Saturday. Upon engine starting up, check engine light is flashing and the engine is running quite rough. This goes on for what I guess to be 15-20 seconds, then engine began to run normally and the CEL went off completely. I never turned the engine off, went for 60 mile trip with a few stops and engine runs great as usual.This same scenario happened when the car was maybe a year old, except the CEL stopped flashing but stayed lite. Since car was under warranty I took it to the dealer and it was diagnosed as a misfire on a cylinder whose number I don't remember and that it was no big deal. I am curious to know if anyone has any thoughts as to what this might be and if it could be the precursor of something more serious.

events, rather isolated events at that, do not signal anything serious.

I assume vital -- oil and coolant -- fluid levels are ok and oil consumption is reasonable?

An '07 with 16K miles is still a 'new' car so it is possible a 'new' coil is acting up. All you can do is wait for it to get worse and then have it fixed under warranty.

If the car is out of warranty then you can decide if you want to replace the coil pointed to by the misfire. It would be nice if you need the error code so you can see if the same cylinder is involved if any more misfires are detected.

Since the car has 16K miles in this case I'd be on board to replacing just the suspected bad coil.

Was the car washed some time before the misfire events? Did the car sit outside? Did the climate change for instance switching from warm/dry to cool and more humid?

Have you been driving the car enough to burn the gas in the tank before it goes stale? Do you buy gas from a busy station, name brand gas and of the proper octane grade?

Any chance rodents have been in/at the car? That they have is not always obvious. A thorough inspection of the car by a professional is often needed.

Sincerely,

MarcW.

Thanks for your thoughts Marc.To answer your questions: no oil or coolant consumption ever; no water and no environmental changes - car stays in attached garage where I have never seen a rodent; the car is driven at least once weekly for 75+ miles and had new fill up of gas the last time driven at same busy Shell station I use when possible; I also suspect a coil. I assume the latest episode would create an error code and indicate which cylinder misfired if indeed that is the case and see if it matches the first misfire. Thanks Marc - I always appreciate your input on the many topics you address.