Tuning, 95% of the time its hard to get rid of hunting on idle with bigger injector's, but its down to tuning. - generally happens on hotter day's.
Again this sounds like the tuning, simply take off at higher rpm.
I would start with the basic's first, cleaning the AFM's, checking plugs, looking for leak's or blockage's etc.
Maby even post you'r inj map off the FC if its possible... this would help.