Thanks Steve for the explanation.
My A/C control are normally set at 72 deg., year round.
This setting is kept all year round, either with an outside temperature at -30 or 95 deg. it has always kept a very constant temperature. At times, I increase or decrease it by 2-3 deg. which result in a slight variation in temperature.
I do not have to apply full throttle to repeat the problem I have.
A normal to brisk acceleration from a traffic light will cause the problem.
Hot air come out all dash vents (including center). And it is not outside air, it is definately heated air. As soon as the vac. returns to normal,(cruising), A/C works perfectly.
Any other idea? Thanks