Chev Uplander, fuel filter, where is it?

In the tank. It's part of the pump module.

If its in the tank, then is it still possible to change it? There is a black block in front of the tank under the body, some wires and tubing connected to it , is this the pump module?

Thanks,

Nope, the filter is in the pump module itself inside the tank. No filter that can be changed. The item your seeing is the vapor recovery and control system.