2003 Grand Marquis A/C Blower Acting Weird

This is something that has been happening for about a year/year and a half. I will have my
A/C running and it will be running normal, then I will open my windows while driving and
depending on how long I keep my windows open, when I close the windows, the A/C does
not blow that much out of the vents, even when I put the air on high. What can be causing
this. Also, the temperature of the air is not effected by this, only the blowing of the air.

The other issue I have been having is that one vent will blow out most of the air and the other
3 vents will blow out a little bit of air. I have to keep the vent that blows out the most air off in
order for the other 3 vents to blow out close to normal. What can be causing this? I asked
my friend's dad and he specializes in the Grand Marquis/Crown Victorias and he could find
out what the problem is or what is causing it. Again, the temperature of the air is not
effected by this, only the blowing of the air.

Thanks for any help you can give.