So my car has decided that a missfire about 10-15 seconds after start up is exactly what the doctor has ordered for it! So far I am scratching my head with it as I had done the following...    Spark plugs genuine Coils genuine put stock injectors back in stock tune file loaded up  changed fuel reg tried NA fuel reg, map and PCM to rule out a PCM failure   I do have a new genuine fuel filter to go in but waiting on flare spanners before