I may can help being how I just ordered a Faria tachometer myself and it didn't come with the connector either. Mine uses a 6 position connector but I bet yours uses the same type as well. You can look for a Deutsch 4 pin (or socket actually) connector from lots of places. And they sell them in silver or gold plated versions too with crimp or solder types also. Search EBay or Summit car parts for them. The racing industry uses them a lot. I have found lots of them on EBay myself... Hope this helps you out... :joyous:
I would go lock at mouser or digikey and see what you can find. They have most everything though it can be hard to find. If Faria can give you any information it would help.