Choke Breaker (Pull-Off)
WARNING: This page is about a different car, the 1993 Isuzu Pickup and 1993 Isuzu Amigo. However, it is still accessible from the selected car via links, so may be relevant.
Apply vacuum to choke breaker. Diaphragm should hold vacuum. If diaphragm does not hold vacuum for a short time, replace choke breaker.