AC vaccum pressure

[SSpeed]

Whats up guys,

Im not sure if im stating this correctly but i have a 2000 LS1 with 150k miles, i believe i am having an air conditioning vaccum issues. when im in 6th gear and mash the accelerator to say go up a hill, the air seem to stop flowing throught the face vents and go down to the floor. Also another condition is after driving for a while on the interstate for about an hour, the air flow (set on the face vents) will reduce its flow significatly but you can still hear the fan going at full blast. This corrects itself if you turn the car off for a little bit and the start it back up.

Any thoughts?

Thanks in advance.

[89RS&98Z28]

Sounds like the evaporator is freezing up. Low air flow. Check low pressure switch. Switching to floor under load is normal, let us know what you find.

[mike171562]

My car shuts off the A/C vents when i got WOT. I have read that the PCM does that to save vacuum or something at WOT.

[SSpeed]

Where would i find the low pressure switch on my 2000 LS1?

Thanks,

[SSpeed]

Anyone got any advice????