Replaced throttle body part,still bucking and no power

Welcome to 2CarPros.

First, what was done to diagnose the throttle body? As far as the throttle position sensor is concerned, you were given good information. It is internal in the throttle body, so if it is doing the same thing with the new part, chances are that isn't the cause.

Have you pulled any diagnostic trouble codes? Have you checked things like a plugged catalytic converter, fuel pressure, engine vacuum leaks and so on? If not, based on your description, the first thing I would check is for a plugged catalytic converter. Take a look through these links.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Here is a link that shows in general how one is replaced:

https://www.2carpros.com/articles/catalytic-converter-replacement

Here is a link that explains how to find an engine vacuum leak:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Here is a link that explains how to check fuel pump pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If the engine is running as you described, chances are the check engine light is on. If it is, you should scan it to identify the diagnostic trouble codes stored. That will help.

Let me know. By the way, I added the links not knowing what has already be done. Those are things that could possibly be associated with a power loss issue.

Let me know if that helps or if you have other questions.

Take care,
Joe