I need to know what's going on with my police interceptor. Can you help me?

Ok so I have a 2003 ford crown Victoria police interceptor and I have a little issue with it. If I start the car and jus drive off I don't have a problem with it until the car heats up at regular tempature. But the issue is when I push the gas it speeds up a bit slow and shakes but if I push the gas down it will automatically jet off with no problems at all no shaking or anything. So what do you think the problem is? I was told it could possibly be my EGR valve but not sure. And I think my headlights have a shortage they if I hold the switch towards me to bright they will come on but in order for them to stay on I can't let the switch go. They actually worked today with out me holding it but when I cut the car off at the store and came back they weren't working again. Is it a electrical issue or is it in the wiper blade switch?