Tunneling transmission of cavity polaritons through a double barrier shows a characteristic intensity behavior, as a function of pump power Pgate. When Pgate is turned on, polariton-exciton interactions induce a shift in the polariton modes confined within the island. (a) When choosing for the incoming polariton flow energy Einc a value slightly larger than the energy of the first mode, no tunneling transmission is observed for low Pgate values. (b) When the gate beam Pgate equals the resonance power Pres, the energy of the first cavity mode is brought into resonance with the polariton flow, the tunneling is quenched, and a pronounced increase in the transmission is induced. (c) When Pgate slightly exceeds Pres, vanishing transmitted signal is observed.