1980-84 All Models Except Diesel
WARNING: This page does not describe the selected car, but rather 125 other vehicles, including the 2010 Volkswagen Routan, 2009 Volkswagen Routan, 2002 Volkswagen Cabrio, 2001 Volkswagen Cabrio, and 2000 Volkswagen EuroVan. However, it is still accessible from the selected car via links, so may be relevant.
Warm engine to normal operating temperature. Disconnect vacuum hose to EGR valve. Test EGR valve by temporarily connecting vacuum hose from distributor retard diaphragm to EGR valve. Engine should run rough or stall. If not, check for clogged EGR passage or faulty EGR valve.