4.3L (VIN Z)

Set parking brake, block drive wheels and place transmission in Neutral or Park. Warm engine to normal operating temperature. Turn A/C off (if equipped). Ensure SERVICE ENGINE SOON light is off.
Disconnect Tan/Black wire EST by-pass connector located near heater housing in engine compartment on S/T Series, or near distributor on all other V6 models. DO NOT disconnect 4-wire connector at distributor.
Connect timing light to No. 1 spark plug wire. Check timing and adjust if necessary. See V6 IGNITION TIMING SPECIFICATIONS table. Reconnect EST by-pass connector and clear ECM trouble code.

V6 IGNITION TIMING SPECIFICATIONS (Degrees BTDC @ RPM)