What is the stock temp gauge going to? Ive found that 210* is between the O and R and after that it gets very "presice" a good bit of movement isnt that mach more heat. It may just be because of the heat, mine does that too and its like 100*+ here everyday, plus its humid as hell.
I had the same problem to the point where the A/C would not blow cold air at all after several weeks of intermitently on/off operation. I ended up replacing the high pressure switch and all is well.
Check the charge on the system... it could very well be low...
Now my car will keep blowing cold air but run hot, based on the useless gage... on a 95' humid day the other day I was able to keep the car comfortable and keel the temp gage at least to the left of the "L" in NORMAL.. really thinking I need an actual temperature gage....
Now on the other hand I know my car needs a radiator (leaks in the winter and based on the crap that came out both times I have cleaned out the system it is probably plugged up too)...