EGR Valve
Remove EGR tube from intake manifold and plug opening. Leave all vacuum lines connected. Start engine and allow to idle. No exhaust gas should be emitted from valve. If exhaust gas is emitted, valve is defective and must be replaced. Increase engine speed until valve opens (about 2500 RPM for 4 cyl. models or 2000 RPM for 6 cyl. models). Exhaust gases should be emitted from valve under pressure, otherwise tube from exhaust manifold to valve is obstructed, or valve is defective. If valve does not open, check for vacuum at vacuum control hose. If vacuum is present and valve still does not operate, diaphragm may be leaking. Check by blowing with mouth. If pressure drop is noted, replace diaphragm assembly. If vacuum is present and diaphragm is not defective, plunger is jammed and valve must be replaced.