Ford - Excursion :: 2011 - Excessive Vapor Smell From Charcoal Canister

I have a 2001 Ford Excursion 6.8L V10. It runs like a champ, gets really good mileage for what it is, but there a strong fuel vapor smell coming from the charcoal vapor canister under the hood. You can smell it outside the truck and the smell gets pulled in through the vents - have to use Max AC recirc.

After checking and testing, I can confirm that the fuel vapor smell is coming from the charcoal canister and not anywhere else on the engine. The smell gets worse as the tank drains: Full Tank - Almost No Smell; Half Tank - Strong Smell; 1/4 Tank - Very Strong Smell.

Here is all that we have tried.-Replaced Fuel Cap (Genuine Ford)-Visually inspected the Evap Lines - Look Good-Visually inspected Fuel Line and Fuel Filter - Look Good-Checked the Fuel System for Leaks - None-Pressure Tested the Fuel System - No Leaks-Ran Multiple Smoke Tests on Evap System - No Leaks-Checked the Computer for Codes - No Codes-Replaced the Charcoal Vapor Canister (Genuine Ford)

We are totally stumped. I searched all the forums and can find issues with plugs, fuel injector o-rings, and leaks, but this has all be checked.