stalls

Hesitates when floored. Sometimes stalls when just started or backed up. Happens when I need power the most. Feels like a fuel problem, but has new fuel pump and filter. Problem goes away when fuel injector cleaner added to full tank of gas. My daughter’s grand am does the exact same thing. 1989 olds 88 and 1997 grand am

Does it do it no matter how full the gas tank is?

My car does the same thing. No matter how much gas is in the tank. I will be driningalong and it with sputter like it wants to die. I put it to the floof andit will die. I too have changed the filter and the pump to no avail. Injector cleaner helps a little but not a ton. I am baffeled.
DG

Have a credible muffler shop do an exhaust pressure test to make sure the cat isn't plugged. Sounds like you might have a restricted exhaust.