A while ago I did the work with removing the intake manifold, to fix the cold fuel leak. I did it with the factory manual.
One thing that the factory manual did not mention, is that there is a direction of installation of that valve, for the 2 lateral hoses.
There's a little arrow on it and it's marked E/G. I re-checked the manual and could not find clear directions on how it should be hooked up, except for reading the main diagram. Anyway, the arrow was pointing in the wrong direction, towards the manifold. I tool the valve out and tried it and it seemed to close fine. But I may have to replace it.