The dreaded subaru check engine light. I was driving 7 people including myself in my outback (it seats five) and I was coming up a hill going into Golden (Colorado School of Mines was partying hard and I designated drove for my friends who paid me). I was doing 60 in fifth gear with cruise control on and I didn't realize how much throttle CC was giving the engine until revs started dropping. Then the CEL came on. So I shifted down to get more torque so I could make it up the hill. I continued on hwy 93 until I got to golden driving the speed limit. I experienced a loss of power but I attributed it just to the ~1100 extra pounds I was carrying. So I dropped them off in golden and drove to Denver and power seemed normal. When I got home my brother helped me pull the air filter, which had burned oil on it right where the MAF sensor is. The airbox had some blow by in there. So as it was 11:30pm the only place carrying auto parts was Walmart. My brother drove me to walmart and we picked up a new air filter and some MAF cleaner (and some goldfish for my drunk friends to munch on). I sprayed the shit out of the sensor and airbox and let them dry and then reassembled the intake. I drove to pick up my friends and was careful not to go full throttle. So I parked it overnight and in the morning the CEL was off. I pulled a P0420 code in the morning.
Any ideas what happened?