Could be alot of things causing this, rather than just guessing I would take it to a shop and have it properly diagnosed by a professional.
Your fuel pump pressure is lowEither a dirty filter or a weak fuel pump will cause thisPressure should be 6 to 10 lbs.
vapor locking hardly happens on any thing that newif you are running out of fuel check for a collasped or weak hose, fuel filter, and check to make sure the vent on the tank and the carb and gas cap are not pluggedif this doesnt help buy a chevy and drag the bronco around lol.
