Misfiring and no clue how to fix
 

Ok I have a 94 civic dx 1.5 and have been having problems with misfiring. I havent been able to drive my car in over a month and its driving up the wall. Ok so here is the scoop. I replaced the distributor, plugs, wires, and the car continues to misfire. When your driving it down the road and you give a medium to heavy load on the engine it begins to misfire and tries to die. At an sit still it cuts out and tries to die. I need help!! anyone got any suggestions. Ohh and today when I started the car to replace the Map sensor the speedometer was acting as if it were the tack... I dont get it can someone please help?