IST1 - Check Idle Speed
^ Start the engine and run until at normal operating temperature.
^ Engine at idle.
^ All electrical loads OFF.
^ Connect Rotunda 88 Digital Multimeter 105-00053, or equivalent as a tachometer.
Data Link Connector:
^ Ground the Self Test Input (STI) connector.
^ Check idle speed:
ATX and MTX 650 ±100 rpm
^ Is idle speed within specifications?
YES -- Go to IST2. IST2 - Check Base Timing
NO -- Adjust idle speed.