Problem began with rough idling and resulted in a backfire and then stalled. Restarted car, called Ford and they ran tests; they sent me home and stated no issue and no sensors. The incident repeated a week later in which the car had to be towed to the shop. Fuel injectors and spark plugs had to be replaced, and since the incident my fuel economy has NEVER been the same. My fuel economy ranged 19-21 mpg on highway and 16 mpg in worst traffic situations (bumper to bumper for hours). I am lucky if I get 13.1 mpg which is calculated by how many miles I drive divided by how many miles I drove from tanking last time. I get 15 if I do straight highway driving, meaning no stopping. Ford states there is no problem and that nothing appears on computer. I feel that technicians rely heavily on computer stas rather than looking into why fuel economy is so poor. I find it strange that an old Ford Econoline for 15 passengers gets better gas mileage than a 7 passenger Flex. If anyone else is having this problem, then I would like to know if they had a better repair than mine.