possed 92 buick skylark quad 4 Please help

the car runs really rough at idle, evens out at around 2000 rpm. while drivingthe car, upon acceleration the engine knocks for a second, and stalls. engine runs rough even when at operating temperature. I have changed coils, coil cover, plugs, plug boots, fuel filter, and ran a fuelsystem treatment, and injector cleaner through the vehicle none of which helps in any way. Please help.