K 2500 Suburban 4WD V8-454 7.4L VIN N TBI (1995)
Idle Speed: Adjustments
Controlled Idle Speed
Before performing this check, there should be no DTC(s) displayed, idle air control system has been checked and ignition timing correct.
1. Set parking brake and block drive wheels.
2. Connect a Tech 1 scan tool to the DLC connector with tool in open mode.
3. Start engine and bring it to normal operating temperature.
4. Check for correct state of PRNDL position (R-D-L) switch on Tech 1 scan tool.
5. Check specifications for controlled idle speed and IAC valve pintle position (counts).
6. If within specifications, the idle speed is being correctly controlled by the control module.
7. If not within specifications, refer to Rough, Unstable or Incorrect Idle, Stalling. See: Powertrain Management/Fuel Delivery and Air
Induction/Testing and Inspection
