Hesitation & Poor Acceleration

Ensure proper spark exists from ignition system.
Ensure ignition timing is correct.
Ensure fuel system performs properly (fuel pump, fuel filter, fuel injector and fuel pressure regulator).
Check EGR system.
Check engine compression, valve clearance, valve timing and timing belt (if equipped).
Check Throttle Position (TP) sensor and wiring.
Check airflow meter or MAP sensor and wiring.
Check oxygen sensor and wiring.
Check cold start injector system (if equipped).
Check Engine Control Module (ECM) and wiring.