my blower motor delays on AC or Vent when accerating, it will restart when I totally let off the gas

the air sounds like it goes into the air box but doesn't come out the defroster, the lower or the front outlets.

have you checked under the hood,small hard plastic vacuum lines,passenger side near the firewall,maybe white in color?.these are bad to get pin holes,crack,split,lose vacuum like you are describing.check them when the engine is running,listen for hissing noises/sounds-air escaping.easy to fix.

This is a 1996 E150. I could only find 1 line that runs behind the blower motor housing,and didn't hear hissing.

ok,i understand it's a van.copy and paste this link,watch the 1st and 2nd video.check that panel on top also.see if you find anything............................................................................................................................................... Ford E350 AC Repair: stops blowing through … www.youtube.com/watch?v=Q_ONYTRi26A