Idle Speed & Mixture: Introduction

Electronically fuel injected vehicles use an Automatic Idle Speed (AIS) motor or Idle Speed Control (ISC) actuator to regulate idle RPM. AIS or ISC is controlled by PCM, which uses information received from various sensors to determine, among other things, idle speed. Curb idle speed is not adjustable. See appropriate G - TESTS W/ CODES article in the ENGINE PERFORMANCE Section for diagnosis of incorrect idle speed.