82maxima

I have replaced everything I think? It just want run correctly spits and sputters when it run. It idles great but want rev at all. The fuel pump that nissian calls for is not the right one the 1985 model has a pump similiar but Its a speacial order and I don't know that it is the correct pump or if there is anything else that could be wrong ( maybe injectors )but it idles fine. The first 60 seconds after cranking the engine it will rev fine but after that it want at all. Any and all suggestions appreciated. Thanks Michael
Chattanooga Tn.