Misfire while cruising

I need help!!
I just finished swapping a first gen JDM b16A into my 1991 Civic SI. The car drives great while accelerating..but..if I just cruise with little throttle input it feels as if it's misfiring. There's definitely a hesitation and loss of power and I can hear the motor sputtering. I changed all the plugs, wires, distributer cap and rotor. That seemed to help a bit but the probelm is still there. Another thing to note, the idle is somewhat unstable but I think it's the idle air control valve.
Anyone have any suggestions??