I have a 1991 Mazda B2600i that is fuel injected.
I was wondering if I could use a gastank/sending unit etc. from another mazda truck that has a throttle body

 

Do you mean carburetor? If so then probably not since the fuel injected units generally have the pump in the tank where carb engines usually use an engine mounted low pressure pump. You would have to get a fuel injected sending unit UNLESS your truck uses a frame mounted pump, then it should be almost exactly the same as the carby one.

 

That's what I suspected. Used parts are hard to find for this thing :/

Thank you for your response!