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Home >> Chevrolet >> 2003 >> Chevy Express H2500 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (Engine Controls - Basic Diagnostic Procedures) >> Idle Speed & Ignition Timing

Idle Speed & Ignition Timing

WARNING: This page is about a different variant/trim than selected.

Idle speed and ignition timing are controlled by PCM. Incorrect idle speed are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly.