Go to Autozone, they will use their ODBII reader and read your code.
Is the car still shaking under heavy acceleration or is that fixed and it is now just revving really high and power cut at higher rpms? I don't know much about crown vics, but if it is cutting power and revving weird at high rpms it could be due to a bad Air to Fuel ratio. This could be caused by a bad O2 sensor or a dirty MAF sensor or something, I dunno if your car has a MAF or not.
It could also be that your sparkplugs and wires are going bad. They will act fine until you start accelerating and inducing load on the engine, and then they can't keep up which makes your engine misfire and throw CELs.