A/C problems

Drive it enough to determine it's "warming" then stop as quickly as you can and feel the suction tube see if it is good and cold. If not you have a refrigeration problem. If so make sure the vacuum/ blend doors in the unit are not dropping out. Remember, your vacuum is always less when driving.

Also some of the Mopar compressors had a suction pressure regulator setup at/ in the compressor. I don't remember just how those work but that could be a problem

Also, I doubt this would give you cooling at idle, but too much oil in the system will coat the evap and reduce cooling.

The above mentioned moisture in the system is a good suspect. What happens is moisture freezes at the metering point.....orifice/ txv because that is where "the cold" LOL happens. Ices up, plugs, warms up, melts, then works again for a short time and does it all over again.