Venturi Vacuum Amplifier
- Check for adequate manifold vacuum. With engine warm and at curb idle, connect vacuum gauge to port "O" on amplifier which leads to EGR/PVS valve. Vacuum should not read more than 2 in. Hg at idle.
- Disconnect venturi hose at carburetor. Increase engine speed to 2000 RPM. Vacuum should not change. Maintain high engine speed and reconnect venturi hose.
- Gauge should register at least 4 in. Hg vacuum. Return engine to idle. Gauge should return to initial reading. If not, replace amplifier.