a/c fan problems

When I am using my a/c, I have my fan blowing out the top vents. However, when I accelerate, the fan stops blowing out the top vents and starts blowing out the floor vents... what the heck can be done about that?

I'm not positive about this, but I think the change in location of air distribution is controlled via vacuum. It could be possible you have a vacuum leak somewhere

The circulation changes are indeed vacuum-electrically controlled. This could be a bad vacuum solenoid control module, which has six colored vacuum tubes going to it. To me, the vac-soleniod itself sounds bad, as it is allowing vacuum to leak to a different actuator during reduced vacuum (accel).