Nismo Chip on a CA18DET ECU help

[Tkca18det]

Sup Guys!!

I got myself a replacement for my blown CA18DET for my 200sx and I got some issues, the one I had was European and the one I got is JDM the ECU Im using is the one that came with it and it says chipped by Sports Craft, I openned up and it comes with a Nismo chip on it.

Now my question is how da hell can I find out what it was done to it, the ECU doesnt have a Serial Port and the chipset just says nismo. Im having a problem with the engine around 3000 reps it starts to jump and wont iddle and then gets better when you pass 3500, around 5 PSI.

Engine came with T28 setup and stock injectorsI have a stock fuel pump as well

Any ideas????

TX