Air Conditioning

My 2007 GMC Acadia air is not working properly. It is not producing cold enough air. When I put a guage on the low pressure hose, it reads about 20 but then the compressor kicks in and the guage goes to about 50. It then goes back down to 20, up to 50 and keeps repeating.

Not sure this is correct. Any ideas?

My 2007 GMC Acadia air is not working properly. It is not producing cold enough air. When I put a guage on the low pressure hose, it reads about 20 but then the compressor kicks in and the guage goes to about 50. It then goes back down to 20, up to 50 and keeps repeating.

Not sure this is correct. Any ideas?

Low charge scenario is compressor on, pulls down to 20, then compressor kicks out- pressure rises to 50, then compressor kicks in...cycling continues.

You have a leak.