Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment: Preparation

Make sure that the following parts are in good order.
- Battery
- Ignition system
- Engine oil and coolant levels
- Fuses
- ECM harness connector
- Vacuum hoses
- Air intake system
  (Oil filler cap, oil level gauge, etc.)
- Fuel pressure
- Engine compression
- Throttle valve
- Evaporative emission system
On air conditioner equipped models, checks should be carried out while the air conditioner is OFF.
On automatic transmission equipped models, when checking idle rpm, ignition timing and mixture ratio, checks should be carried out while shift lever is in N position.
When measuring CO percentage, insert probe more than 40 cm (15.7 in) into tail pipe.
Turn off headlamps, heater blower, rear defogger.
Keep front wheels pointed straight ahead.
Make the check after the cooling fan has stopped.