sorry to bring up the burried thread but...my 05 is doing the same...my aunt gave the truck to me and filled it up previous to giving it to me. That night the gas gauge dropped to BELOW E mark and stayed there, it jumped back up when the gas level was below 3/4. This will trigger a CEL. However Ford did tell me it was "bad gas" and to use Chevron Techron(didn't help...).

When you fill the tank above 3/4's it will error, but below that my gauge works fine, and the CEL will go off. Must be a bad sender....and they did mention the dirty fuel card.

Is making a fuel tank gauge that difficult? Manufacturers have been making flawless gas tank gauges/sending units for decades and yet Ford needs to change the technology..making it all electronic..and now are adding even more TSB's and recalls that shouldn't be necessary in the first place! (IMO).