Silgs300

I replaced the Ac compressor, drier, expansion valve and, orings. When i bought this car the AC didnt work, my mechanic friend recommended from reading the gauges the compressor was shot. A vacuum was pulled and it was holding so I added freon, a whole big can and a little bit from a second can. The compressor works fine when I'm moving, as soon as I stop or slow down enough the compressor kicks off and AC light flashes. The radiator fans are spinning.

I have used the search button and it sent me to dead ends