92 Heater Prob

Greetings!
Okay, let's try this on on.
The heater and a/c in my 92 Caprice work great.
But on the highway, if you start to climb a hill, pass or otherwise accelerate, it will change from defrost or floor to vent position and just BLAST hot air at you.
Now I know we don't complain about "too much" heat much around here for the next few months, but this blast from the vents would bake you if left alone! Do I have some kind of vacuum issue here?
Comments appreciated, group.
Jim.....

I've got the same issue with my 92 Custom Cruiser. It hasn't bothered me enough to find out what's wrong.

What’s happening is your AC compressor shuts off when the extra horse power is needed for the acceleration. It is a vacuum problem. Check your MAP sensor, it monitors the vacuum pressure in the manifold. When the vacuum drops to a certain point, it sends a signal to the PCM which in turn shuts down your compressor to gain the extra h/p needed. :banghead:

C.
Thanks for the informative answers to my questions.
I've only had the car for eight months. Issues are minor and there's lots of potential for upgrades.
We love this car!
Thanks, Jim..........