Difficult Start (Cranks Okay)

Ensure sufficient secondary spark is available.
Check air induction system for cracks and restriction.
Ensure vacuum hoses are not disconnected or damaged.
Ensure fuel system pressure and volume are correct.
Ensure fuel system residual pressure is correct.
Ensure fuel injector operation is correct.
Ensure EGR valve operation is correct.
Check for cracks and poor connections at throttle body.
Ensure ignition and valve timing are correct.
Check ignition coil primary connections and wiring harness.
Ensure ignition coil resistance is within specification.
Check Engine Coolant Temperature (ECT) sensor operation.
Ensure electrical harness and connectors are not broken or loose.
Ensure PCM has correct voltage supply and is properly grounded.
Ensure engine has sufficient compression.