Recently my 93 Civic started giving me trouble. I'll try to describe the problem as best I can. Whenever the car is decelerating, the needle on the tach bounces up and down, by about 500 RPM's. The transmission is automatic and whenever I shift from drive into park, the same thing happens. The check engine light has recently lit up also. The speedometer stopped working at around the same time, although that could have just been coincidence. Does anyone know what the problem could be? And if so, does anyone know how much it will cost to fix this? I don't know much about cars, so any help would be appreciated.

this is just a shot in the dark but u might have an electrical problem, maybe some of your wires are crossed or cut..it could also be a few blown fuses..your best bet is to have someone check it out for u