Need help, car stuttering

I have been having a stutter problem for a couple weeks now, it pulls the code p0500 which is the speed sensor, but I have already replaced this with a new one. My idle will hang sometimes and the car will stutter under low rpms going down the road. I have noticed that I can get the check engine light to trigger by reving the engine while sitting still and it will be that speed sensor code again. I have checked for vacume leaks replaced plugs, not sure what it could be, but I did pull the vacume to my egr and notice there is no vacume from that line. When is there supposed to be vacume on that line, I can rev the car and still can't fell any vacume on the line, I traced the hose and it looks like its hooked up to a vacume source, anyone know what it could be, this is a 98 cobra, thanks

should not be, new fuel filter/pump and injectors, the egr is also new

I keep getting this P0500 which is speed sensor malfunction, I have already replaced this sensor, but It still will set the code, I notice that the check engine light comes on while I am reving the car sitting still and it will be p0500 speed sensor. I checked the volts to the speed sensor today and could not get a volt reading with the key in the on position, I think I am supposed to have 5 volts when the switch is on. Would this cause the problems that I have been having with the car stuttering in low rpms??? I will have to trace the wires back to the computer and see if there is a cut or something.