New Problem...for me

I installed the Edelbrock nitous system on my car, (350, stock dished pistons on a stock bottom end, RPM Air-Gap intake, 750 holley, vortec heads, msd ignition, comp 268XE cam, 1/2 fuel line with a holley black fuel pump 150ish GPH) and when I hit the gas it will spray until about 4500 rpms then stop the nitrous but keep flowing fuel. When it cuts out at 4500, it will come back then cut out again....like it pulses the nitrous.

My question is, What could be causing this to happen?

We checked the hob switch and it allows nitrous to flow above 5psi fuel pressure. My bottle pressure was about 1000psi, and I don't know what to check now.