Need help with AC issues

1993 mack ch

New receiver/drier & condenser. blew out the lines looking for a blockage. They were clear but im thinking every now and then a piece, o ring maybe will block it up from time to time not all the time. Before we blew the lines out we couldn't get it to take a charge (local AC guy did that) now after getting it to take some it's intermittent working and not the coolest. Condenser fins are fine and cac is 2 yrs old fin are good not blocked.

What would be next step? Evap core? Before this it would freeze you out on low

@AModelCat i was reading a post somewhere you seem knowledgeable on ac. Kinda stumped here and so was the AC guy we took it to last fall. The little bit i do know is you'll get false readings on both sides, if something internal is f'd, don't remember the part they were referring to