gas gauge acting erratic

Hello,

It is likely due to a faulty fuel level sending unit.
The fuel level sending unit is located in the fuel tank, it is a part of the fuel pump assembly.
In order the replace the level sending unit the fuel pump assembly needs to the replaced.

The fuel pump unit can be accessed thru the inside of the vehicle, by removing rear center seat cushion. There is an access panel under that cushion. Simply remove that to get to the fuel pump.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.