Losing power?

Yep, it sounds like a fuel pump is going out and you should drain the fuel and replace it with new. We can confirm the failure by doing a fuel pressure test. This guide can help, and you can rent a pressure gauge for cheap at the auto parts store.

General Specifications
Regulator pressure .................... 350 kPa (3.5 kg/sq.cm, 49.8 psi)

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

Here is how to change the pump out and drain the fuel as well:

https://youtu.be/Q5MH2gnyFH0

Please do not lower the fuel tank when it is full of gas, it is heavy, and you might lose control of it. Check out the images (below). Please let us know what happens.