My car has been running bad a while and today i did a KOER self test and got codes 12, 21, 18, 44, 94. Also did cylinder balance test and got code 2. Book refers to Thermactor air system not inoperative on left and right side but not sure what that means. I'm having a hard time finding a real mechanic to work on it so trying to fix myself. Last mechanic kept it over a week without even touching it. Symptoms are low gas mileage like 8ish MPG, low power, studdering, uneven idle for a few seconds after startup. 93LX 5.0 manual not stock.