Sorry i dont know anything about Emance. I do know Nistune and Nismotronic and calumsult.
Start with this if its tuned to a desired psi (say 15psi) if you go over 15 it will lean out since the tune doesnt compensate. I would start here. it needs to be logged so you can pin point the issue it could be a Pegged Maf, to high of injector duty, pump maxxing out etc.
And an answear to Alex's question would help also.