95 eclipse fault code

My daughter has a 95 eclipse non-turbo car. The check engin light is on, and I checked the code using the key on/off method. The code is 12 43 55. I was told the 12 and 55 are just the start stop test indicator. She has take this car to several different shops and has replaced the plugs, fuel pressure regulator, and the throtle position sensor. Non of these things seem to fix the car completly. I was told by one shop that the fuel pump pressure is supposed to be 70 psi and the pump in her car is only putting out 50 pis. The mechanic said that this was low but still within the spec (is this correct?). A new pump is about $150. Should I replace the pump. Any help would be greatly appreciated. Thanks