Engine Lacks Power

Inspect throttle cable adjustment.
Ensure air intake system is not restricted.
Test EGR system for correct operation.
Ensure fuel system pressure is correct.
Ensure ignition and valve timing are correct.
Test purge control valve operation.
Test vacuum switching valve operation.
Test throttle position sensor operation.
Test coolant temperature sensor operation.
Verify throttle valve opens completely when accelerator pedal is fully pressed.
Check transmission for correct downshift (A/T).
Inspect exhaust system for restriction.
Ensure engine has sufficient compression.
Check cylinder leak down.