Engine Lacks Power

Check throttle cable adjustment.
Verify air intake system is not restricted.
Check EGR system for correct operation.
Ensure fuel system pressure is correct. Use ohmmeter to verify correct fuel injector resistance.
Ensure base timing is correct and timing advance system is functional.
Check purge control valve operation.
Check vacuum switching valve operation.
Check throttle position sensor operation.
Check coolant temperature sensor operation.
Verify throttle valve opens completely when accelerator pedal is fully applied.
Check transmission for correct downshift (auto. trans.).
Check exhaust system for restriction.