Engine Lacks Power

Ensure throttle valve opens completely when accelerator pedal is fully depressed.
Check for limited airflow sensor plate travel caused by defective screen in airflow sensor plate boot.
Ensure air intake system is unrestricted.
Ensure fuel system pressure and volume are correct.
Ensure base timing is correct and timing advance system is functional.
Check coolant temperature sensor operation.
Check transmission for correct downshift (A/T).
Check fuel tank filler tube for tampering of restrictor. If tampering has occurred, check catalytic converter for lead contamination and exhaust system restriction.
Check for poor quality fuel containing insufficient cleaning additives.

NOTE: Prolonged use of poor quality fuel can cause injector clogging and carbon build-up on intake system.