[en] The resistivity and magnetism for the Cu_1-x-yAg_xIr₂S₄ (x = 0, y 0, 0.05, 0.1, 0.15; y = 0, x = 0, 0.05, 0.1, 0.15) system were investigated. A Peierls-like phase transition occurs at T_MI∼226 K for CuIr₂S₄. The transition is suppressed in the Cu_1-xAg_xIr₂S₄ system, which is attributed to that the substitution of Ag, with its larger radius, for Cu releases the pressure of Ir-Ir. The transition temperature T_MI increases slightly with vacancies increasing in the Cu_1-yIr₂S₄, which corresponds to the increase of pressure. Our explanation about the pressure release and increase can also be applied to clarifying the pressure effect which is still an open question. The magnetization rises at low temperatures below T_MI. We suggest that it is attributed to remnant localized electrons, which do not participate in the Peierls-like phase transition, accompanied by spin-dimerization in this system. By fitting the experimental curves, we find that about 0.7% of the Ir⁴⁺ ions do not participate in the Peierls-like transition. The contributions of Pauli paramagnetism, Landau diamagnetism, Larmor diamagnetism and Curie magnetism can be distinguished