I have had problems with my 2000 Saturn SL2 intermittently refusing to start. In the past few months, I have changed the spark plugs and wires, fuel injectors, ignition coil packs, EGR, crank position sensor, fuel pump, fuel pump relay, and fuel tank pressure sensor, and even though it starts, it runs very rough and constantly sounds on the edge of stalling out. Any ideas what else it could be?

how about 0 2 sensor? Or maybe distributor?

classic signs of old worn out or dirty fuel injectors. try this video cleaning first https://www.youtube.com/watch?v=bKGI9N_yWd0

As you can see from my list, I already replaced my fuel injectors with brand new ones.