u/Cheffk4

I’m trying to help a friend get his WRX back up and running and I’m stumped. His fuel pump failed on the highway so he towed the car home and we’ve replaced the fuel pump and gaskets. We left the battery disconnected and allowed the cars to idle for a bit to relearn fuel mapping. The car starts and idles fine but when you press in the clutch at a stand still there’s a high probability it will stall. When the cars in motion and we push the clutch in to change gears the vehicle immediately stalls. Not throwing any codes. Any ideas what the culprit could be?