a/c is cold seting at stop light,but whin you take off it starts getting hotter

Really you need a full A/C inspection. Just putting in a charge with out really knowing what is wrong can actually do harm.

I have the same experience in my 1999 Jeep Grand Cherokee Ltd, discharged old freon, vacuumed, still the same thing, wasted money on freon and labor. Thought of replacing the accumulator assy, dont purchase it at the stealership, buy it at ebay, price is reasonable. Installed it yesterday, vacuumed the whole system, then recharged it, its now steady at 55 degrees and when rev up the engine it goes down to 50 degrees and low side pressure is only at 25 with outside ambient temp at 90. (im in vegas, we have only two seasons here, HOT and HOTTER) hahaah. good luck.. hope this helps.

DON'T KNOW