 Driving this new 2016 transit, 250 medium height roof since February. With out warning van randomly loses acceleration, engine won't respond to accelerator and runs rough. Have to coast over into the break down lane and shut off/restart several times before van will drive again.  Dealer telling us parts are backordered and 3 weeks out at best. Indicated they have had several other Transits in the shop for the same issue claimed to be the throttle body. Ford will not provide rental reimbursement.