Issues with Rev's

Hi guys i need some help, i got my 6g about 2 years ago and ever since i have had problems :cry:
I have so far converted the airbag suspension to standard shocks, replaced ecu due to capacitor leak, water pump, and recenlty a gear box.

I know have a problem where in a stationary position regardless of gear the revs fluctuate between 1000rpm - 2000rpm doesnt matter what im doing but it does this every one second. so it sounds like im sitting there reving it. problem is when the car gears down it crunches into place because of the constant push. anyone had any similar issues? i tried to get an error code from the ecu but tried everything with no luck getting a code. any help would be apreciated.

probably the isc(idle speed controller), a stepper motor located right below the throttle body. it will have an electrical plug, and it is held on by 2 little bolts with 8mm head. you have to reset base idle, then the ecu can control the idle. think of it like a pendulum. when you set base idle, you put the pointer exactly in the center. then, if the pendulum(idle) starts to increase, the ecu, using the stepper motor, brings it back to center. if it starts to drop, the ecu brings it back up. a quick test is to remove the isc, connect it back up, and have someone turn the ign on, but not start. the tip of the isc will cycle in and out, and then stop. if it starts vibrating, it is bad. this is a wear item, dont go used on it, cause it might be bad, too.
the other issue might be an air leak. get a can of carb cleaner, and spray it around the intake where air could be leaking. if the revs increase, you found it.

ill give this a go as no one else can sugest anything to me :?
thanks by the sound of what u said it fits my problem.

thanks.

you might want to check your thermostat to becuase mine revs like that the first time i start it everyday untill it warms up.