Ignition miss?

I have a 2002 912 uls in an s-7 and at run up at 4000 rpm the ignitions perform good but in the air when you do a mag check at 4500 the left shows about a 200 rpm loss and the egt’s rise to about 1425 at 5500 rpm the right shows a significant drop and the left normal,and the egt’s will rise to over 1500 f could it be that at around the 4500 rpm range that it is starting to use the main jet circuit and it is too lean and gets worse as rpm increases,I did drop the needles one notch a while back but I never checked for a lean condition because the egt runs within the parameters given by rotax until the other day I was just checking the ignition while flying and noticed this condition.I checked all the usual things new plugs,checked mechanical fuel pump and electric Checked all grounds and plug in connectors to ignition.