93 Grand Am

I recently had the cat converter, coil packs and a hose running to the fuel pump regulator replaced o my car. It ran great for one week now its hesitating again and doesn't want to shift gears. The car does not idle rough. The rpms increase but the car refuses to shift, worse uphill. Downhill it drives fine. What could be going on?

The vacuum modulator is the first think I would look at (check if the hose is still connected).