Hi and thanks for using 2CarPros.
First, here is a link that shows in general how one is replaced. I am adding this because it shows more clearly how it is done.
Here are the directions specific to your vehicle. The attached picture is of the filter which is located under the vehicle.
1990 Oldsmobile Ninety-Eight V6-3800 3.8L
Fuel Filter Replacement
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Filter Service and Repair Procedures Fuel Filter Replacement
FUEL FILTER REPLACEMENT
NOTE: Before replacing a fuel filter it is necessary to relieve fuel system pressure, see MAINTENANCE PROCEDURES/FUEL SYSTEM PRESSURE RELIEF.
The fuel filter is located under the rear of the car, in front of the fuel tank.
WARNING: To reduce the risk of fire and personal injury when the fuel line is disconnected, cover the fuel line with a shop cloth to collect the fuel, and then place the cloth in an approved container.
1. Raise car on hoist.
2. Disconnect the fuel lines from the filter using a back-up wrench to prevent damage to the fuel lines.
3. Remove the filter from the car.
1. Install the new filter in position loosely.
2. Using new "O" rings, install the fuel lines into the filter.
NOTE: Use a back-up wrench to prevent filter, "O" ring, or fuel line damage.
3. Torque line fittings to specification 30 Nm (22 lb.ft).
4. Secure the filter to the car.
5. Lower the car.
6. START the engine and inspect for leaks.
I hope this helps. Let me know if you have other questions or need help.
Thursday, December 6th, 2018 AT 7:52 PM