How do I change feul pump 97 chevy lumina 3.1 l

You must remove the fuel tank which is underneath the trunk. Here's the procedure for removing the pump.

REMOVAL:

1. Before servicing the fuel pump the fuel system pressure must be relieved.
2. Disconnect the negative battery cable.
3. Raise the car on a hoist.
4. Remove the fuel tank.
5. Remove the fuel tank sending unit and pump assembly by turning the cam lock ring counterclockwise. Lift assembly from the fuel tank.
6. Pull the fuel pump up into the attaching hose while pulling outward away from the bottom support. Take care to prevent damage to the rubber insulator and strainer during removal. After the pump assembly is clear of the bottom support, pull the pump assembly out of the rubber connector for removal.

NOTE: Inspect the fuel pump attaching hose for any signs of deterioration. Also check the rubber sound insulator at the bottom of the pump. Replace damaged or deteriorated parts.

INSTALLATION:

1. Push the fuel pump assembly into the attaching hose.
2. Position the fuel tank sending unit and pump assembly into the fuel tank. Use a new "O" ring seal.

NOTE: Care should be taken not to fold over or twist the strainer when installing the sending unit as this will restrict the flow of fuel. Also, verify that the strainer does not block the full travel of the float arm.

3. Install cam lock over the assembly and lock by turning clockwise.
4. Reinstall fuel tank.