I have a 80' 300D with the old style pump. My car blows out light grey smoke on idle and alot more when acceling from a red light. The car shuts off If I rig the door lock vac switch. But no leaks in door lock system. I get about 19 reading on the vac guage. Is the diaphram leaking, is that why the smoke is coming out? should I upgrade to a newer style pump?is it possible?