V8 Engines

Remove air cleaner assembly from engine and allow it to cool for 15 minutes at room temperature. After cooling, look through air cleaner snorkel to observe position of the air valve, it should be fully open to outside air. Reinstall air cleaner and connect hot air tube and manifold vacuum hose. Start engine and observe position of air valve, it should be fully closed to outside air. Move throttle lever rapidly to approximately 1/2 to 3/4 opening and then release it. Air valve should open and then close. Allow engine to warm up to operating temperature and observe position of air valve, it should be fully open to outside air. If air valve does not close at room temperature with vacuum applied, check for mechanical bind in the snorkel, vacuum motor linkage disconnected or vacuum leaks in hoses or connections at vacuum motor, thermal sensor and intake manifold. If air valve mechanism is operating freely and no vacuum leaks are detected, connect a hose from an intake manifold vacuum source directly to the vacuum motor. If the air valve closes, thermal sensor is defective and must be replaced. If air valve does not close, vacuum motor is defective and must be replaced.