Have you made sure the flue is unobstructed? Maybe the pothole knocked something loose and blocked the airflow. There's usually a spiral baffle in the flue to slow down the airflow just enough to allow more heat transfer. I'm not sure if it matters when running on electric but I would think heat is heat. Maybe it fell out of place?
Is there warm air coming out the vent when it's running (on either electric or propane)? It sounds like your unit is cooling but poorly. It could be external (venting) or internal (cooling unit issues).
