HELP Please, Not running good

[strokeit]

I have a 2000 7.3 f250 and its not running good at all. first over the winter i noticed white smoke when startup and driving down the road, this has still continued, now as of a week ago it has started loosing power after bout 5min drive. it starts fine, runs ok but with white smoke until about 5 mins into my drive, it bogs down with no power and barely wnats to move, i then pull over, shut it off, and restart to have power back for maybe 2 minutes and repeat til i get home. it has code p1211. i have replaced fuel pump, fuel filter, and cleaned screens in sending unit bc it acted as it wasnt geting enough fuel. But still no success. Any ideas? this is my daily driver and i desperatly need help! Thank You in advance!