1997 Buick Lesabre Fuel pump

Remove the fuel tank. First disconnect the battery, relieve all pressure in fuel lines, carefully remove fuel lines, and un plug electrical connection at tank, remove filler hose and vent hoses, carefully remove any remaining fuel in tank, remove gas tank straps. Drop tank and remove retaining ring. Then carefully remove pump unit. Then follow instructions that come with new pump. Good luck.

It is unlikely that this would cause a rough running condition. It is more likely that the fuel pump is not producing enough pressure or sending enough fuel.

Here is the procedure to replace the pump so you can see if anything jumps out that you may have missed. However, I would suggest starting with measuring fuel pressure to make sure the pump is performing properly.