Hi everyone I'd like to start off by saying my van is a 2003 e350 super duty 7.3 PSD.

The problem I'm having with the heat is that there is barely and air flow on the drivers side floor. It doesn't matter if the **** is set to floor or mix. The passenger side air flow is great. All the dash vents and defrost work great as well.
I have to turn the heat on max to keep my feet from freezing in the winter but then it makes it so very uncomfortable for my passengers. Thanks in advance for any troubleshooting techniques you can share.

 

Your dash vents or air ducts are the same an with any other engine--that's the good news.

There isn't or shouldn't be any sort of controllable vane that would cause your low flow condition on just one side. I'd run something like a fish tape (similar to electricians use) from the opening near the floor to see if something has found its way in there.

Can't be 100% sure but the fish tape should be able to pass thru to the passenger side floor vent---assuming your control is on Heat, not in Mix, Vent, Defrost or either A/C settings.

Let us know what you find.