Surging over 5000rpm with good O2's and PSI???

Everytime I take the car over ~5100ish rpm's on N20 (100shot), the car surges VERY badly. Bottle pressure is ~950 and O2's never drop below 900. Any ideas? Did the same on a 75 shot too.

My car did that when I first got NX. A MSD ignition fixed the problem. So if you don't have that I'd look there first. :)

I've got a 6a hooked up. Maybe it's bad?