Idle high

[punka44]

Hi. I have Eclipse 1991 GS NT and I've problems with idle speed, when motor is cold. When I start up (I don't move with car) rpm goes to 1500 rpm (good) and slow down to 750. But If I move with a car, the iddle speed goes up to 2400 rpm and then oscilates between 1500 - 2200 rpm. When I'm running it's OK, but if stay for stoplight and put my gear to neutral, than it makes the same oscilation for a moment and than goes down to 750 rpm. When the motor heats up, everything OK. It's terrible and nobody know's where's the problem. Thank's everybody for help.
Peter.

 

[BoostedTT91]

when i start my car when its cold it revs up to 2300 rpms and then it will go down to 2000rpms and just go back and forth between 2000-2300 crazy fast and when the car finally warms up it will sometimes keep a steady idle at 1500 but it will still surge from 1500-1850 slowly once its warmed up. I dont know where to look anymore
i have tested the following
ISC-Good
checked for any leaks
tried swapping ECU's
i have tried everything i know and it still continues.
ANYBODY have any ideas or can help me??