1997 Honda Civic Question: MY honda feels like its dying on me.

Up until a few months ago my honda was working just fine. then it started to have a check engine light that said the pistons were misfiring and a sensor was going off. Took it to a shop right away they replaced the wires plugs , oil change, checked it all out and nothing had changed when i took it for a ride. It has been rumbling all the time, check engine light constantly blinking me to death, the worst part is that it has a total loss of power and cant make it up to 55 without feelin like im killing it like a stunt driver in a car chase. and when going uphill it dies so that it goes over 5000 rpm just to keep it up to 50 miles an hour which is way way way to low to keep up with the speed limit making it VERY unsafe passing or just driving at all! I have checked everything from the fuel filters to air and oils and fluids and everything i could possibly do. has new tires and brand new parts in it now and still wont cooperate! there is a big loss in mileage do to me having to hit the gas all the time to even make a decent speed. I hate this so much and im ready to set this car on fire ( because the freaking honda dealership doesnt have a clue and tried to charge me 100 dollars to tell me NOTHING) someone people help me.