The air sensor plate on your K-Jet fuel injection system actually moves UP under increased airflow. At the other end of its mounting arm are the "plungers" that regulate fuel flow, in conjunction with the control pressure regulator. If you remove the bell-shaped rubber boot connecting the air-fuel control unit to the throttle body you can see the plate. It should be perfectly concentric in its opening. You can gently raise it up to see if it is binding.

If it only opens part way, it is telling the control unit that the engine is not demanding much air, so the unit will then not deliver much fuel. This is one sure recipe for low power, but there are plenty of others.

Terminology on the 'CI' abbreviation can be confusing, but Volvo seem to use CI to refer to the K-Jet system (Continuous Injection) and 'CIS' to refer to Constant Idle Speed systems. The Germans (ie: Bosch) spell continuous with a "K"...hence K-Jet.

Good K-Jet info here: http://www.k-jet.org/articles/information/k-jet-in-detail/