Toyota Repair: 1999 Toyota Rav 4, toyota rav 4, 1999 toyota rav 4

Question
My car has a PO401 Trouble code, EGR flow problem. If I open the valve by hand the engine stalls indicating the valve passages are not clogged. I connected a vacuum guage with a T-fitting at the EGR valve and roadtested the car. I have less than 5 inches of vacuum at the valve. That doesn't sound like enough vacuum to operate the valve. What can I do to solve the problem.   Thank you. Mike

Answer
There are two common causes for this, the egr modulator valve, located on a bracket directly on the egr valve and the egr vacuum switching valve(VSV) located under the intake manifold, replace them both or try just replacing the modulator and see if the light stays off if not the vsv will need to be replaced as well.