Take a look and make sure the electrical connection to the Evap Canister Vent Solenoid Valve which is located above the carbon canister is securely in place.
As the next step in trouble shooting this problem, I would disconnect the hose located between the carbon canister and the Evap Canister Vent Solenoid Valve. With this hose disconnected the only thing left in the vent path is the carbon canister (evap canister). Attempting to fill with the Evap Canister Vent Solenoid Valve disconnected will confirm one way or the other if there is a problem with a clogged canister or Evap Canister Vent Solenoid Valve problem. If canister will allow vent path then the problem lies further downstream i.e. Evap Canister Vent Solenoid Valve.
Diagrams for Evap Canister Vent Solenoid Valve indicate that this valve is Normally Open.
In my experience solenoid valves that state they are Normally Open are open when deenergized (aka "shelf position") and this would seen to make sense for the situation when you are filling the tank with the ignition key off.
I am not positive that, in this case, Normally Open may be referring to when the truck is running though, IDK.
Let us know what you find.

 

Another thing you can try is to provide a temporary vent by pulling gas tank line off purge valve under hood , i know one guy was doing that to fill his tank temporarily until he could go to work on vent . If its not mud or insect blockage then a hose is pinched or carbon canister is partially blocked . The vent solenoid can be blown thru when deenergized which is the normal state .
It doesn't take much back pressure to shutoff pump or for fuel to back up ' I guess its possible your carbon cannister is full of fuel and it is not being successfully purged when purge valve is commanded to open and apply vacuum pulling air thru vent valve up thru carbon cannister and into intake manifold .
I would be very leery of putting too much pressure on that fuel system .
Anyway you have at least a partial blockage of vent system . The vent solenoid from everything I know is open in the deenergized state and only closed during a pcm commanded vac test of tank and emission loop .If you can't easily blow thru it then its bad . The carbon cannister can be rebuilt I think or get one from junk yard . Make sure you test the purge valve on the firewall ,it is normally closed when deenergized . It only opens to purge tank and carbon cannister thru the vent valve with outside air coming thru carbon cannister with fuel vapors being picked up . Then being burned in engine .

 

The reason I say check purge valve is if it doesn't open the carbon cannister may become saturated with fuel since it would not purge . Some clips from the battery 12v will open it and you can blow thru it . They usually start to leak when closed and you can blow some thru it when deenergized . This causes rich conditions on fuel trims .

 

sorry it's been a minute I was out of town and had alot going on. Sound advise that I will check in the am. It does have a rich smell to it when I crank it.

 

AnthonyawhHave you resolved this issue and if so please post the solution? Give us an update. Feedback is important so that we all learn solution paths to these issues.

Thanks in advance

 

No I have not resolved the issue. Now I'm going to drop the tank again and make sure the lines in the tank leading to what appears vents got kinked and see if the spring loaded flap at the bottom of the fill tube is getting stuck. If that's not it then I guess I'll cough up the 400.00 for a new evap cannister.

 

My local (mobile AL) "Pick-A-Part" lists carbon canisters for $7.99. Seems too inexpensive for that massive canister but that may be the price for a used one

 

Do they have a way to purchase it online or do you have to actually go pick the part? It's worth 7.99 to find out.

 

Give them a call
Barry's U Pull It Auto Parts
(251) 653-2925
They are open today. Open at 0800 Central
If I were you I would look locally, there are, in general, U-pull auto parts dealers in most of the larger cities. Those places are fun to cruise through and most have parts that are dirt cheap. The cars/trucks that go there are stripped of Cats and gas tanks but otherwise start out whole. They stay on the lot 3-6 months and then go to the crusher. Plastics parts have zero value in the crusher so they generally sell cheap.
Inventory varies but, again in general, 2010 and older can be found in these lots.
Good searching!

Also Rockauto.com has brand new vapor canisters for between 119.79 and 295.79 (Motorcraft)

 

I would buy the junk yard cannister and vent valve . Maybe buy the whole tank assembly .