1996 dodge neon highline 2.0

My neon keeps quitting but will start right back up after sitting for a few seconds. It was giving me code numbers 12 54 55 so I had my sensor replaced for my camshaft,In also had fuel filter , spark plugs, wires replaced reset computer it was fine for a day now it is doing it again it is giving me the same codes again, I dont know if this will help but the car runs great until its warm then it starts stalling like it not getting gas.The man at the garage said honey I can't find anything wrong with your car,look I may be a girl but I know what the car is doing, any advice would be greatly appreciated. Barbie