Emissions

I know absolutely nothing about the emissions, and was wondering which of the parts control the amount of air that the throttle body uses. I have a 1994 Metro (1.0), and it seems starved for air. What exactly does the egr valve do?

All the EGR valve does is introduce exhaust gas into the intake passages of the throttle body and intake manifold, this theoretically reduces emmissions by re-burning the harmful stuff originally burned by the power cycle of the engine. You might want to look at the throttle position sensor and check the butterfly valve that allows air flow through the throttle body!