1990 Oldsmobile Delta 88

There are a number of things that can contribute to that. Here are a few.

1) Using substandard parts (Delco recommended)

2) Running the tank low on fuel

3) Weak tension on the spring contacts at the harness plug causing voltage drop to the pump

4) Rust or debris in the fuel tank

5) Clogged or restricted fuel filter

6) Voltage drop to the pump from other causes in the circuit.