Just got my car back out from changing back to the stock intake manifold. First thing very apparent to me is a quick oscillation of RPM. About 750-1200 back and forth every second. I tried smoothing out my VE to help soften this and it didnt really help. Watching my gauges, while this is happening it doesnt make a difference if the IAC is in Closed loop or not. It can be at a constant 50 steps and it still oscillates rapidly. With this intake the car usually idles in the 46-42 step range. Even tried messing with the PID settings to get it to catch and slow down the RPMs, and although it was in CL, it still couldnt stop it. Normal Idle map is 55 kPa, it was going from 48-72 while it was hunting. Of course my AFR was all over while doing this, probably because of the over run fuel cut setting. Sound like a tuning issue or a vac leak somewhere?