Ford is profitable in Europe. Gas is more expensive for the most part in Europe, therefore fuel prices are not a direct reason why Ford would not be profitable in North America.
Foreign Car companys are profitable in the United States, when you fill up a Toyota do they charge you less for the gas? Toyota,Honda are profitable in North America, I am talking about the car lines that are actually built here, not the ones vehicles they import.
I disagree with your reasoning that fuel prices are the only reason why sales are "falling". People are buying more cars in North America now then they did in 05, just not Ford vehicles. The amount of car sales has increased, not decreased since gas prices have increased.