E150 Van OBD Test failure - please reply / help!

On the EVAP leak, I would first check to make sure the fuel cap is on tight. If any corrosion exists on the lip of the neck, clean it off and apply some vaseline around it. It doubt, get a new cap. A cap would cause a large leak in the evaporative system, but a rotte fuel filler neck could do the same. If the above doesn't work, find a good independent shop that can smoke the system.

On the Egr flow, I would pull the egr valve and clean it, and check the passageways for obstructions. Use a good carbon removal cleaner. Castle make cleansrite.

This may be contributing to the lean codes, but I am starting to venture into BS :lol:

On the EGR fault I would not only pull it and clean it, but would also check vacuum and electrical lines leading to it for any problems or breaks. You could have a rotted diaphragm in the EGR valve itself causing it to not open or not open very far, or you could have a bad EGR position sensor sending wrong readings.

Since both banks are running lean, I would think weak fuel pressure that's affecting the entire system rather than a plugged injector somewhere which would likely only affect one bank. Unless you had plugged or partially plugged injectors on both cyl banks. I would check to make sure your air filter is clean and free of abstructions, fuel system presssure checks out ok, fuel system is squeaky clean, there are no vacuum leaks anywhere, both intake air temp sensor and mass airflow sensors are working correctly (though we don't suspect those because a code would be set for them as well if they weren't working well) and check to make sure there aren't any vacuum leaks anywhere. Those are things you can easily do yourself, and those are the things that most directly affect fuel delivery. Good luck.