Special tools will be required to block the IAC passages to adjust the throttle plates. These professional ones expand by rotating the handle after installing. Less expensive, nonadjustable plugs are available from Thexton in most auto parts stores. They’re marketed under the name IAC adjustment plug; you’ll need two. Always lubricate the rubber with some light oil before installation, or it will stick to the throttle body. Remove the electrical connector from each IAC motor. Note the new balance screw.