Is the ISCV needed?
 

I have been chasing a high idle for about 2 years and have just gotten to the point where I said #€£¥ it! But I am currently in the middle of a complete rebuild and I have decided to attack the idle issue once again. This time I ripped everything apart and looked for a cause and came across the ISCV where I found a ton air getting to the IM. I did some research and couldn't find a full on reason for the ISCV. So I plugged the air line part of the ISCV and started the car, with a adjustment of the idle screw the idle issue was fixed. Not too sure what the use of the ISCV is, but my car is running better without it.

Coming from DSM land, removing or blocking off the ISC in those cars only results in cold idle being high or slightly erratic. Once warmed up idle would settle out and the car would behave normally. It's done frequently to DSMs with no other ill effect.

what ECU do you have that's controlling it?

Since I have a mix of cold/hot weather, and coupled with a/c and headlights, I wouldn't leave home without my iacv. My idle is baby bottom smooth.

I think he means the thing that uses the coolant flowing through the tb to control idle. Normally has wax in it. Pretty common thing to see on motorcycles and I think I remember 1.6s having it and 1.8s not.

misread the acronym.

Running mspnp. Temps at startup are about 50f and it stumbles for a moment then settles out at 1k to 950 rpm. Was at almost 2k at startup with ISCV.