Hight idle problem

First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

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.

I would next check for a vacuum leak. Follow all vacuum lines and inspect for breaks or cracks. Look near the corner of driverside corner of firewall for the little vacuum lines to be rotted or cracked.

Do the enginescan thing if your service engine light is on. Take your air duct off and take choke cleaner and spray the throttle plate on both sides, they getgummed up with oil and stick. Check for vacuum leaks andcheck your fuel pressure it shold be 60-66psi. If it's low and you change the fuel pump change th filter as well.

The idle air control valve could be sticking try cleaning it out and see what happens. Also clean out the throttle bore plate

Yes, it might be a vacuum issue? Make sure the throttle valve is closed. Clean the throttle-body check the iac.

If this is a throttle body unit they tend to blow the gasket under the unit. A can of choke cleaner sprayed around the bottom will tell. If the idle changes up or down you've found the leak. Also the hose going to map sensor gets soft and sucks together make sure that is in good shape.

I screwed up ith the answer. These have to be checked to see if the injector harness is connected correctly as they will lose contact. Also the injector lines inside the intake crack and can leak. It may be that as well.

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