I have a '98 Sport that is having a problem with the A/C system. The problem is that the cooling is weak, almost like it is half vent, half conditioned air. I do feel cool air mixing in at times. The cooler outside it is the better it works, the hotter it is, the less it works. Could this be related to the blend door issue?

 

It can be the blenddoor issue indeed, but there is more to check.
Besides the A/C system itself (pressure, content of fluid) you can put the ventsystem on A/C-max, this closes the valve located halfway the waterpump and heatercore, so it must give maximum cooling effect.
Also check the blenddoor by putting the system in 'vent' position, without A/C, and play a little with the temp-**** to check response in heating.
Success, Tony.

 

Have had it on Max and negligable difference in air temp. May be a little cooler, but that could be the force of the air coming out as well. In vent mode, I do get heat as with all settings.