I had that FF23 on and off for years Joe. I tried everything and changed every sensor even the MAF.
As far as the EVAP system goes, I bought another purge valve and swapped out the carbon canister too and went as far as replacing those pricey blue valves. I replaced all the injectors and the FPR as well. Nothing made it go away permanently, It would go away for a while after a reset - sometimes for as long as a few months but always came back.
I read through the engine management .pdf FF23 pages so much I practically knew it by heart.
It did get fixed eventually, but only last spring. Tenacity!
After exhausting every known cause and swapping out all that stuff, (thank god I had a low mileage parts car!) the only possible reason for the car getting too much gas was … it was getting too much AIR. Unmetered air.
Vacuum leak. Not a big one, a very small and possibly intermittent one in my case …FF23 always got thrown with a warming engine just as it came out of open loop…never a hot car. That un-metered air must have come from a leaking intake gasket at the manifold. When the manifold came off to replace the water rail last spring, I saw the old gasket was in rough shape …probably re-used sometime in the past by the PO. New gaskets - no more FF23.
So Joe, have a look for small vacuum leaks before tearing into the evap system!