Idle Speed & Ignition Timing

Idle speed and mixture are controlled by Powertrain Control Module (PCM). No adjustment is required. PCM controls Idle Air Control (IAC) motor for proper idle speed. See TEST TC-25A in appropriate SELF-DIAGNOSTICS article.

Ignition timing is controlled by PCM and is nonadjustable. If vehicle is equipped with a distributor, DO NOT attempt to adjust timing by rotating distributor. If distributor is rotated, fuel system synchronization will be changed. If distributor is rotated or removed, check fuel system synchronization. See FUEL SYSTEM SYNCHRONIZATION under FUEL SYSTEM in ON-VEHICLE ADJUSTMENTS - TRUCKS & RWD VANS - CNG & GASOLINE article.