Fuel Injected

Ensure idle adjustment is correct.
Use stethoscope to verify operational noise coming from fuel injector(s).
Ensure sufficient secondary spark is available.
Ensure engine has sufficient compression.
Ensure there are no vacuum leaks.
Ensure fuel system pressure and volume are correct.
Verify vacuum hose routing is correct.
Check PCV system for restrictions.
Check operation of coolant temperature sensor and airflow meter.
Check air valve or ISC valve for malfunction.
Check electrical connections at airflow meter or throttle body.
Check for cracks or poor connections at airflow meter or throttle body.
Check EGR operation.
Check O2 sensor for fluctuating voltage output above and below .45 volt (0-1.0 volt) with engine at 2000 RPM.
Verify throttle position sensor has correct adjustment and resistance value.
Check for purge valve malfunction.