IST1 - Check Base Timing
^ Connect Rotunda NGS Scan Tool 007-00500.
^ Start the engine and run until at normal operating temperature.
^ All electrical loads off.
^ Connect Rotunda Inductive Timing Light 059-00005, or equivalent.
^ Run the engine at 2000 rpm for 2 minutes.
^ Accelerate the engine 2-3 times.
^ Run the engine at idle for 1 minute.
^ Select ENGINE.
^ Select WORK SUPPORT
^ Select IAC VALVE ADJUST
^ Press TRIGGER.
^ Accelerate the engine to 2000-3000 rpm 2-3 times, then run at idle.
^ Check timing.
NOTE: If NGS Scan Tool is not available, disconnect the Idle Air Control (lAC) solenoid connector, then check timing.
^ Is timing 15 degrees ± 2 degrees BTDC?
YES -- Go to IST2. IST2 - Check Idle Speed
NO -- ADJUST the timing by loosening the distributor bolt and turning the distributor housing. TIGHTEN the distributor bolt to 14-17 N.m (10-12 lb-ft).