So, I'm having a few different issues with my A/C. First off, It doesn't blow all that cold. It blows significantly cooler out of the side vents than it does out of the center vents though.

I know there is some kind of vacuum issue, because anytime I step on the throttle, my vents redirect down towards the floor. Where do I need to start diagnosis?

Last, but not least, after the A/C has ran for awhile, it blows HOT air out of the vents. I'm assuming the evaporator is freezing up, and its running a defrost cycle?? What kind of pressures should we be seeing at idle with ambient temps in the mid 80'sF to mid 90'sF??