Idle Speed & Mixture (Gasoline): Notes

NOTE: DO NOT attempt to adjust idle mixture and idle speed, which are controlled by the Electronic Control Module (ECM). Incorrect idle speeds are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly.

NOTE: Controlled idle speed and IAC count can be checked using scan tester. See CONTROLLED IDLE SPEED & IAC COUNT . Minimum idle speed adjustment can only be performed on the 7.4L engines. See MINIMUM IDLE SPEED ADJUSTMENT (7.4L ONLY) heading below.