Idle Speed & Mixture

NOTE: Idle mixture on fuel injected models is controlled by control module and is not adjustable. Controlled idle speed and IAC count can be checked using scan tool. See CONTROLLED IDLE SPEED & IAC COUNT table. For controlled idle speed adjustment procedures, see the ADJUSTMENTS - 7.4L article. Minimum idle speed adjustment can only be performed on the 7.4L TBI (VIN N) engines. See MINIMUM IDLE SPEED ADJUSTMENT.

CONTROLLED IDLE SPEED & IAC COUNT

Application

Idle RPM

⁽¹⁾ IAC Counts

7.4L CSI Auto. Trans. ⁽²⁾

575-625

Varies

⁽¹⁾	Add 2 counts for engines with less than 500 miles. On V8 engines, add 2 counts for every 1000 ft. above sea level.

⁽²⁾	Automatic transmission in Drive.