Fuel injected vehicles with idle speed control motors should NOT have the TAS (Throttle Adjusment Screw) adjusted for any reason. Refer to illustration below. The TAS functions as a stopper when the throttle valve is fully closed. During production, the TAS is accurately set by measuring the airflow rate past a closed throttle plate. Any adjustment to this screw will affect PCM control of idle speed.
Customers complaining of low idle speed should have their vehicle repaired using the Workshop Manual.
NOTE: Tampering with this screw will affect the idle contact switch and/or throttle position sensor settings. This can lead to rough idle and difficulty in diagnosis of idle quality concerns.
The TAS locations on the examples below may vary depending on model year of vehicle.