help please struggling with an intermittent misfire

Hello

Please help bought my first e46 about 3 weeks ago now and for the first week it was lovely to drive however now it has developed a terrible intermittent misfire. Its a 2003 320i touring automatic. I have had it scanned many times with only a few codes showing which havent really given much insight.



misfire cylinder 6

misfire cylinder 4

misfire cylinder 6 fuel cut off

and o2 sensors in the exhaust which i have been advised will show up due to the misfires and un-burnt fuel etc going through exhaust



Initially it seemed to be cylinder 6 misfiring however now it seems to have moved to cylinder 4 interestingly if i turn the car off and back on it seems to go away for a few seconds.



I have changed the following through reading forums and advice given to no avail. in addition to this i have also sprayed all around the inlet with tons of brake cleaner to identify if there has been an air leak to which there was no change in the idle which leads me to believe that it is not sucking air from anywhere.

fuel filter

spark plugs

both cam sensors

2 new coil packs.



Please help i am happy to pay someone for an accurate diagnosis as to the cause of this problem however when i have it scanned it seems to only be throwing up the same fault codes.



Thanks

Terry