No. 1 Control Valve
- Remove air cleaner and warm engine to operating temperature. Stop engine. Disconnect vacuum hose from carburetor to EGR control valve at control valve.
- Disconnect vacuum hose from intake manifold to vacuum amplifier at amplifier and connect this hose to open port of EGR control valve.
- Pinch off intake manifold vacuum hose to EGR control valve, while engine is restarted. Release hose. Engine will idle very rough or stall. If idle does not change, clean or replace EGR valve.