I have a 2001 Kia Rio with about 65000 miles. The check engine light is on constantly. I have taken it to the dealership and they said that the codes that came up suggested a problem in the mass airflow system, we replaced the O2 sensor and the catalytic converter and cleaned some connectors, however the light has remained on and now they are stumped. They said they went through every part that could be responsible and couldnt find anything else wrong. Could the problem be in the mass airflow sensor? Additionally, the car tends to surge a bit while driving down the road, as if I turned on the AC. Could this be another symptom of the air intake? They thought that problem was with the engine mount, but couldnt tell which one was bad.