At some point I downloaded a service manual here on the forum, but I don't seam to have the MPI Fuel system section for it. My Montero is Idling fast, about 2500 on start up and the ICS (IAC) drops it down to 2000 or so after warm up. I've checked the TPS, it checks out ok, I checked for vacuum leaks, and I even pulled the throttle body, cleaned it and reinstalled, still nothing. I even fidled around with the TPS and still it avaids me. I'm wondering if my MAF sensor is screwing up. It runs perfectly fine down the road, just idles fast. Any help would be greatly appreciated.

First try cleaning the throttle-body and ISC per this link:
http://www.4x4wire.com/mitsubishi/tech/throttle_body/
While you have the ISC disconnected, you might as well check its coil resistance per this link:
http://www.stealth316.com/2-isc-iac.htm
Let us know how it runs after doing the above.

Thanks for the info, I have already cleaned the ISC and the throttle body. I didn't check the coils, only because it steps down fine during warm up. It'll drop the RPM 500-700 rpm.

I have a copy of the MPI chapter of the service manual in .pdf - lemme know if you want it and I'll put it up for you. <img src="/forums/images/graemlins/wink.gif" alt="" />

-DougB

My '91 did the exact same thing. I replaced the ISC and it fixed it. It cost about $300.00 or so from NAPA. You may want to read your computer codes before playing the parts changing game. There should be some old threads on computer codes in the archives.