1974-78 Models

Visually inspect entire EGR control system and clean as needed. Replace hoses that are damaged. With engine coolant temperature below 104°F (40°C), raise engine speed to 3000-3500 RPM. The EGR valve should remain closed. With engine coolant temperature above 134-145°F (57-63°C), EGR valve should open and allow exhaust gas recirculation at 3000-3500 RPM.