Misfire on cylinder 4 when first started
 

Has anyone experienced what seems to feel like a misfire when you let your 996 idle in the morning? If I start the car and immediately drive it I don't experience any issues, but if I start the car and let it idle (after a minute or so) it throws a engine light (misfire on # 4). Has new coils... Dealer thinks is may be the lifters, but they are not sure (expensive guess). Any ideas

Are you getting any other codes other than the misfire?

Have seen vacuum leaks show random misfires on individual cylinders, what are the adaption numbers doing?

You took it to a Porsche dealer? Well if they can guess that so can all of us. Did they say that they eliminated the possibility of a faulty injector? An intake or faulty exhaust valve would cause a cylinder misfire so lifters would not do any good. I have even seen a intermittent crank sensor do the same. They could be right however that is an expensive guess. JW:confused:

Yes you have a good point there.

If there is a vacuum leak (which can cause misfires) then it would most likely show a code for o2 sensor out of range, limit exceeded.....i forget the p code for that......

If just the misfire code on #4 I would first swap the #4 coil with cylinder 6 as it's easy to get to......then see if the misfire stays.
Id the coils are new there is the possibility the connector isn't” clicked” onto the coil properly, why were the coils replaced?

As bell says, swap the coil packs and make sure they click in place.

If there's still a misfire on 4, it's possible you have a weak lifter, faulty injector, vacuum leak.