I have an 01 Forester and recently have had a hesitation from the engine. There is a code its for low cat efficiency and cylinder 3 missfire. I looked at the air fuel sensors with a scan tool and they seemed to be reading normal. After some further checking the front one was not responding so replaced it and the problem remained. Did the test from the scantool for the MASS airflow sensor came back fine. Checked the MAP sensor and it tested fine. Checked the plug in cylinder 3 and it was white as a ghost. So checked the injector to see if it was plugged seemed to be fine. Switched cylinder 1 and 3 injector and plug problem got a little better but is still there. Any suggestions?