A**uming the transmission is a AW4 automatic.
The correct idle speed is 700~750 RPM in DRIVE. It is checked after the engine and transmission are both up to full operating temperature--after about 20 minutes of operation. Second set of hands, parking brake set AND with foot on service brake pedal, shift transmission into DRIVE and check the idle speed.
Your problem is most likely the IAC/IAC port in the throttle body. Buy yourself some throttle body safe aerosol cleaner. Remove the IAC, clean the throttle body inside, the IAC port, the throttle plate. Clean the IAC but be careful with it--you can break the pintle and then you are going to need a new one. Use the spray cleaner, cotton swabs, old toothbrush (or your roommates toothbrush). Put it all back together, get it back to operating temperature and check the RPMs again.
The IAC is a stepper motor that receives an extend or retract signal from the ECU to control the idle speed--there is no mechanical adjustment for the idle. There does exist a small allen screw that can move the throttle plate--don't screw with it, it is NOT for idle adjustment, it is there to prevent the steel throttle plate from slamming fully closed in the alloy throttle body and damaging it.
The IAC can become "lazy" with age and then it should be replaced.
PS--don't provide power to the IAC when it isn't mounted, it has no built in stops and overextending it will break it.
Good luck.