I can't imagine the motor mount making the engine run poorly and cause the gauges to go nuts.
Is it possible that there was a ground knocked lose or something? I'd start going over the connectors and harneses in the car, check all the grounds.
Sounds like a Motor mount died when you hit the bump and maybe knocked something electrical lose.
2011 Focus SE 5 Speed 36k - Blue Flame Metallic - Added Rear Swaybar
2000 Jeep Cherokee Sport 115k - Lifted with mud tires.