Throttle slows down, no power?

Hello,

The most common reason for low power output is a faulty throttle body. Inspect the throttle body, if there is excessive dirt and grime build up inside then the performance of the vehicle can suffer.
It will be a good idea to clean all the component on the throttle body.

Here is a helpful guide:

https://www.2carpros.com/articles/throttle-actuator-service

That cleaning should include the idle air control valve as well as the mass air flow sensor.

https://www.2carpros.com/articles/idle-air-control-valve-service
https://www.2carpros.com/articles/mass-air-flow-service

Is the check engine light illuminated on the dash?
Typically low power out put is trigger by sensors for engine management system. When a sensor goes bad it can trigger the check engine light.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I have attached diagrams for your reference.

Please let me know of any questions.
Thank you.