Ford A/C

On all the Ford trucks I have ever owned, when I accelerate, the A/C stops blowing on me and sounds like it is blowing on the windshield. When the truck is just cruising or idling the A/C blows cold. The service guy tells me the A/C is fine, so I am very fusterated with this. After all, it is hot out here in Texas. Anybody have any ideas what this could be? Anybody having the same problem with their Ford trucks? Any advice or suggestions would be wonderful.

This is normally caused by a vacuum leak. The vacuum motors/air doors are operated by vacuum on most older vehicles, some newer ones have electronic actuators. There is usually a small vinyl vacuum line feeding the heater controls which goes thru the dash on the pass side near the evaporator housing . Theyre bad about dry rotting, crumbling from heat, or rats and mice chewing on them causing a leak. At idle the vacuum is strong enuff to overcome the leak, when you gas on it the vacuum drops and the heater controls/air doors move which sometimes causes hot air to be mixed with the cold and the air blowing from a different vent.