Mysterious misfire

[Truckster1]

Hi guys,I have an 2005 x5 that has a bad misfire under any kind of load. For the longest time it wouldn't even throw a code. I replaced plugs and coils. Originally I replaced the coils with bremi ones. The problem continued. I finally took it to bmw they said its because I didn't have factory Bosch coils and wanted to sell me more new coils. I said no and took it back. I returned the bremi coils and replaced them with Bosch coils from our parts supplier other than bmw. I'm not sure if there is a difference in the Bosch coils from bmw and the Bosch from other parts places or not but the car still has the same issue. It finally came up with a multicylinder misfire cylinders 1 2 and 7. We have also replaced pcv valves. Not really sure where to go now I have read about problems with the eccentric shafts in those but don't wanna just start throwing parts at it. Anyone have any suggestions?