cars before 95 wont store any codes.it has to be an active fault.If you put a scanner on it while its running,and acting up , look at long term fuel trim.it'll be LT fuel trim.If its higher than -12 percent youre definitly running rich. Check for a bad MAF sensor.It should be around 4.5 - 5 grams per second at idle.Around .7 volts.Sometimes with a bad MAF if you unplug it , it will run better.Only OBD2 cars will store codes in memory when the fault isnt active