1975-79 Dasher
- Warm engine to normal operating temperature. Disconnect vacuum hose from distributor retard diaphragm and temporarily connect this hose to EGR valve.
- Engine should run rough or stall if EGR valve is working properly. If engine does not run rough or stall, check for clogged EGR ports or for faulty EGR valve.
- To check vacuum booster, connect vacuum gauge between vacuum booster and throttle valve port. With engine at idle, vacuum reading should be 2-4 in. Hg. If vacuum reading is not specified, check throttle valve port for blockage.
- With specified vacuum obtained, connect vacuum gauge between vacuum booster and temperature control valve. Vacuum gauge reading should be 2-4 in. Hg. If vacuum reading is not as specified, replace vacuum booster.