The MAP sensor is located directly above the II portion of the E-TECII logo, and is attached with a single bolt. Before doing anything with the sensor itself, check the thin vacuum tube attached to it and running underneath. It's not unusual for that tube to develop cracks on either, or both ends.

Instead of checking it (which tends to do even more damage), you can just carefully wind electrical tape around both ends of the tube. If that resolves the issue, then you can buy one of those tubes online and replace it anytime going forward.

The tape on the intake hose is a standard repair for these Aveos. I've had my '05 taped (and re-taped) for 7-8 years (it's been so long I've forgotten when I taped it originally).