Toyota Repair: 96 Avalon Check Engine Light, valve stem seals, manifold vacuum

Question
The check engine light is on and the diagnostics test said there is insufficient flow to the egr valve. I have since cleaned the egr valve and replced the egr valve modulator. After doing this I cleared the code but it has come back on. There is also excessive bluish exhaust smoke on some startups.

Answer
The first step is to apply direct vacuum to the
egr valve port, this can be done using a vacuum pump or running a vacuum hose directly from the intake manifold(not ported vacuum) it has to be full manifold vacuum, with the engine at idle applying vacuum should create an engine misfire and in some cases kill the engine, if nothing happens the egr valve is either inop or the passage in the intake chamber is clogged and not allowing exhaust gases to go into the intake. If the egr system tests ok then there are two other possible causes, the egr VSV could have an intermittent problem, it's located under the black engine cover, or the EGR gas temp sensor located on the throttle body is defective or the wires are not connected. The smoke is normally do to worn valve stem seals.