code 66 mystery

i have a code 66 on my oldsmobile eighty eight royale 1992 and i had my ac compressor changed over the summer and it was fine after that so i dont know why im getting a Low A/C Refrigerant Charge. my car stalls and jerks until it warms up

any ideas what could be bad

Low refrigerant, but this should not cause stalling, different issue.

so whatever is making my car run like shit isnt anything on the belt

The stalling and jerking cold, should be scanned cold when this is happening, looking for coolant temp sensor problems or other related issues that normally pop up only when cold.