Engine Difficult To Start Under Hot Conditions

Ensure fuel system performs properly (fuel pump, fuel filter, fuel injector and fuel pressure regulator).
Ensure ignition timing is correct.
Check fuel pressure control vacuum switching valve (if equipped) and wiring.
Check coolant temperature sensor and wiring.
Check idle air control valve (if equipped) and wiring.
Check cold start injector system (if equipped).
Check air temperature sensor and wiring.
Check Electronic Control Module (ECM) and wiring.