Here's the scenario:

99 Subaru Outback with 72k, auto tranny. Anytime she needs to step on it the car will not respond and rpms will hit around 4500 before the tranny will kick down; merging, etc. is scary at best for her b/c one day the wrong situation will arise. However, if she runs through the gears manually she can get around without much fuss.

Any ideas?