a/c pressure at higher rpm

[raphy rod]

hello.Another dilemma with a/c.My 95 atx with r134 has a reading of low side about 35psi and a high side of 190 while the compressor stays on.It is about 80degrees outside.When i push the gas,the low side pressure goes down to about 20 psi,and the high side goes up to about 200.this is when my air stops getting cold.if i let it idle,seems o.k.What would make the low side pressure drop low when gas is pushed.is it supposed to drop much lower?how do i resolve this issue?it's not fun without a/c in vegas.Thanks for the help