1993 Cadillac Seville High Idle

Its called idle speed control valve-

Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and a defective idle speed speed control motor/valve stuck in the extended (high idle speed) position/throttle position sensor. Also the throttle plate could be binding in its bore and kinked accelerator cable, coolant temperature sensor might not be operating properly misleading the computer that the engine is still cold and computer throwing fuel at it raising the idle speed.

You may not have to replace anything, clean out your throttle plates with carb cleaner and a tooth brush, make sure your EGR ports are clear also, look down the throttle plates and there are 2 tubes, these are EGR ports. Then you will have to ck the voltage to the TPS it should be.5 volts with the Idle actuator fully retracted and idling at 500 rpms

your TPS controls your actuator for Idleing. If its not at.5 your idle will be high or to low depending on the situation and an idle relearn will have to be preformed