97 Tahoe A/c Issue

[leboyd]

My '97 Tahoe seems to blow reasonably cool/cold air from the A/C when driving under 50 or so mph. When I'm at hwy speeds (65-70), it just doesn't seem to keep up. This is in TX, with 100 degrees but it seems fine at slower speeds.

 

I tried to put more freon in, but it wouldn't take any - indicating to me that it had enough.

 

I changed the compressor, dryer and such out a little over a year ago.

 

Any ideas?

 

TIA.