gladiroth

hi my names Ethan. i have a 91 lumina that has been giving me problems. its been running really rough lately and throwing codes.. i knew that car hadnt had a tuneup in a while so i changed plugs and wires, discovered the cps was cracked so changed that to. still ran rough and when i tried to check for codes on it it would only flash 12... so i took it to a shop and had it scanned. the scanner said that the knock sensor, coolant temp sensor, tps, and the-sensor-that-plugs-into-the-airbox-that-i-dont-know-the-name-of had all been over charged. so i got my alternator tested and yup it was bad so i replaced that and the 3 sensor (tps, knock, and coolant temp) that i knew where important. tried starting it.. still ran rough but it cleared up and idled but still said it was throwing a code. so i checked it.. it gave me a 43 and a 53. i check the knock sensor to make sure all was well and it was fun so tried starting it again now its throwing a 15-43-53 and wont star or idle with me on the gas... just looking for suggestion on where to go from here.. thanks guys