The rubber thing is the Bottom half of the air flow meter. It fits over the throttle valve, and there is a steel band as a clamp. If the air leak is not causing problems with starting or idle I think leave it alone.

To replace you would need to remove fuel lines to injectors, remove fuel lines to fuel distributor, unplug eha and position sensor, unbolt and remove air flow assembly from manifold. Than take apart air flow assembly replace rubber part and if it is older car you need a new fame because the new rubber part does not fit.