996 Multiple Misfire Codes
 

I have a 2003 Porsche Carrera 4 cab with a 996 engine. I am getting multiple misfire codes p0300, for p0303, p0306 #3 and #6 cylinders when engine is warmed up. No codes before then. What could cause this. Thank You in advance.

If anyone is interested. This may be helpful.
Engine ran fine until it reached maximum temperature then codes and
misfires occurred.

I decided to invest in a Durametric Enthusiast cable unit.
Started car and idled to max temperature.
When Durametric plugged in unit showed misfire codes on cylinder #3 and #6.
Used Live Data function and selected Misfire counts to all cylinders.
Found #3 to be misfiring 8 times per second.
Found #6 to be misfiring fro 60 to 80 times per second.
All other cylinders showed 0 counts.
I checked all other sensors Maf, O2, etc. all within manual tolerance.
I then removed Coil packs from cylinders #3 and #6 tested for resistance both packs checked out.
I then found visual signs of a crack on top of each coil pack.
I Ordered and replaced the two packs and plugs.
Restarted the test exactly as before. No Misfires on any cylinders.
Road tested for several hours (Fun) and still no codes.
Yay! Problem Solved.

Determination:
Coil packs showed good with resistance check.
Packs show cracks with visual inspection.
Packs failed when heated due to expansion of visual crack maybe allowing spark to go to ground
or pack failure.

Invest in Durametric! It already paid for itself!!

Picture of cracks?