Fluctuating idle and fuel filter

[red_sir]

I have a s13 SR and the idle is fluctuating on cold starts. It starts up right away and idles at ~1300rpms, sits there a good few seconds, then it'll drop to the point where the car stutters and almost dies, then jumps back up to 1300rpms and repeats the cycle. It does this for a couple mins until the car warms up a bit. It didn't use to do this, but it started right after I changed in a Z32 fuel filter. Seemed like a pretty easy install but I think I managed to mess something up. Any ideas what the problem is and is it related to the fuel filter install?

BTW, I'm running a microtech ECU (w/ map sensor) and the connector to the idle control unit (4 wires, 2 from the AAC valve, and 2 from the thing beside it) is not plugged in, it never had been, so I don't think my problem is related to that.
Modified by red_sir at 4:33 PM 11/10/2005