Engine Hesitates Or Misses

Ensure electrical harness, connectors and wires are not broken or loose. Check ECU connector pins No. 9, 11, 13, 17 and 25 all input signals to ECU.
Check alternator for low output. Check all electrical connections for tightness.
Check injector operation and opening duration. Check injectors for leaks.
Check turbo and Automatic Performance Control (APC) systems for proper operation.
Check throttle position sensor for proper adjustment and operation.
Ensure mass airflow meter filament is not broken and burn-off function is working.
Check induction system. Check for air leaks downstream of throttle valve, using pressure tester. Pressure should be 5.8-11.6 psi (.4-.8 kg/cm² ). Visually inspect between mass airflow meter and throttle housing.
Ensure fuel pump is operating. Check fuel pressure and pressure regulator. Check for leaks or restrictions.
Check temperature sensor operation.
On 900 Series, check oxygen sensor resistance and voltage.