return brings out air-bubbles when i crank; when i stop its return comes normal on 2004 Ford F-350 Super Duty

when i crank the car the return brings out air like bubbles but when i stop cranking the return comes normal. i have change the fuel pump but am still have the same problem.

Asked by for the 2004 Ford F-350 Super Duty
Out of fuel.
2 more answers
Out of fuel.
fuel pump is poss failing