1986 Chevy Camaro idle to high

Either your throttle plate is sticking or you have a vacuum leak. Try cleaning the throttle plate on both sides with choke cleaner. Also the iac as it may have gunk in it as well. The iac is the oblong hole by the throttle plate. Look on tune up on the site here and it's the first picture to show what it looks like. It's under the air duct.