FixVault

Idle Speed

  1. Idle speed is controlled by an idle speed control valve. Ensure engine is at normal operating temperature, valve clearance is correct and all electrical accessories are off.
  2. Connect dwell/tachometer to engine. Ensure idle speed is within specification. See IDLE SPEED & CO LEVEL  table. If idle speed and CO level are not within specification, check idle speed control valve or intake manifold for air leaks. If problem is still present, check for stored DTCs in PCM.
    IDLE SPEED & CO LEVEL

    Application Idle RPM (1) (2) CO Level %
    6-Cylinder & V8 650-750 .5
    V12 530-630 .5
    (1) With A/C off and transmission in neutral.
    (2) Maximum specification, measured at exhaust manifold. See ON-VEHICLE ADJUSTMENTS article for additional information.