When I start the AC cold air comes out but after a few minutes air is not cold any more, I checked a few things, what might be wrong considering what is listed below

Pressure on the low pressure side is 60 PSI
AC colling fans near the radiadtor are working

 

Might be a sticking valve.
I would have a shop check it for you.

 

hard to say without high and low pressures....could be low refrigerant level.



after the system goes warm, rev the engine up to 2500 rpm and hold it there for 20seconds...does the system turn cold again?

 

possible low freon and or possible capillery tube.An d pressures would be nice to know!!

 

Under what set of conditions are you getting 60 on low side? If it is with system off it could tell your ambient temp, but if it is with system running , that we need to know.

 

with the system off 60psi is normal at rest but when system cycling low side show be 30psi and the high side depending temp out side humitaty high side should be approx 180 too 200 psi.