1996 Pontiac Firebird car continues to sputter and lose som

I RECENTLY REPLACED ALL 3 COIL PACKS, PLUGS, WIRES, AND THE THROTTLE POSITION SENSOR WHICH WAS SHOWING TO BE THE PROBLEM WHEN PUT ON THE COMPUTER. HOWEVER, AFTER ALL OF THIS WORK, MY CAR IS STILL SPUTTERING AND LOSING POWER. MY CHECK ENGINE LIGHT IS NOW BACK ON AS WELL. ANY SUGGESTIONS TO WHAT IT COULD BE??? I ALSO HAVE THE ABS LIGHT ON NOW THAT SAYS ABS INOP. CAN U TELL ME WHATTHIS MEANS?? I KNOW IT HAS TO DO WITH MY BRAKES, BUT I AM UNSURE WHAT THE INOP STANDS FOR.