No. 6 misfires after warm up. The PCM checks engine conditions and when certain thins reach certain temperatures it runs several tests and one of these tests is a misfire test. I swapped out the spark plug and coil and still got the misfire code. Did a spark check, during start up the spark checker flashes during crank but as soon as engine is running (2 seconds) the spark checker stops flashing (the cylinder goes into a no spark condition) I checked the cylinder opposite No. 6 and that cylinder continued to fire (just like it should) so I moved that coil to No. 6 and got the same performance as before, spark during crank, no spark during run. What causes this?