@Troubleshooter................
lolzzzz, troubleshooter in trouble.....I dont think that the problem is in fuel tank, but you can give a try to drive the car without the fuel tank cap to make sure the there isnt any pressure devaloping when you are having 1/2 tank.....another thing is go to some 1 who has OBDII scan toolkit, attach itwith your car and drive, so the fault will be shown on laptop if its only doing during drive.