1991 Subaru Legacy. Check engine light is on. I checked and wrote the codes it gave me by plugging in the black and green wires under the dash. I replaced the O2 sensor and the light was still on. I decided to have a subi mechanic plug in the OBD 1 port and help. He reset the codes and told me someone put the wrong computer in the car. The car runs awesome at 360,000 miles and I just wanted to pass DEQ. The second he unplugged his computer from mine my car runs differently. It is now hesitant to accelerate. I have cleaned the air filter and cleaned the Mass Air flow sensor. Still no dice. I will look into cleaning the injectors and throttle body. I feel it's a sensor dealing with air/fuel regulation. Help?