Difficult To Start (When Hot Or Cold)

Test ECT sensor operation.
Ensure fuel is of good quality.
Inspect ISC actuator for malfunction.
Inspect IAT circuit and output.
Ensure fuel system pressure is correct.
Ensure fuel injector operation is correct.
Ensure ECM has correct voltage supply and is properly grounded.
Ensure sufficient secondary spark is available.
Ensure ignition coil resistance is within specification.
Ensure ignition and valve timing are correct.