Caprice V6-262 4.3L (1987)
Thermal Vacuum Valve - Carb: Testing and Inspection
Secondary Vacuum Break Thermal Vacuum Switch (Svb-TVS)
With engine at normal operating temperature, the SVB-TVS must be open. Check by applying either engine vacuum or auxiliary vacuum to the inlet
port on top of the TVS and checking for vacuum at the outlet. If there is no vacuum, replace the TVS.