Recently my 300 was miss firing at high rpms and now it is running off 5 cylinders or sounds like it is... I had this problem a while back and it corrected it self... Now it isn't correcting its self.. My wiring harness is pretty much trash for the connectors to the ignition coils and the injectors from the age of the vehicle and not sure if this is the problem... If anyone has had this problem please let me know how you fixed it.. I am sure this is not a uncommon problem for this age of a vehicle nor how they are selling wiring harness's for this car on ebay like crazy.. Any help would be great as I will be able to avoid the $100 an hour rap charge they will hit me with over at nissan..