Need some help figuring out how to get my recently acquired 1991 300zx N/A to idle properly. So long story short, the car idles perfectly fine with the MAFS disconnected and is throwing no error codes from the ECU (blinks out 55). I put on a new MAFS from z1 along with a new harness and it still does the same thing. I've checked fuel pressure and it is normal (around 40psi). So far I have replaced fuel injectors (came with the car), new fuel filter, new MAFS, new MAFS harness, new air filters, new spark plugs, cleaned out fuel tank and fuel pump. When the MAFS harness is plugged it only idles for maybe a second or two and then dies. I have two harnesses disconnected and coolant lines not hooked up properly. I believe one harness is the knock sensor, and i cannot find where that plugs into. The other harness I think is an o2 sensor. There were many hoses and harnesses disconnected when I picked this car up, and I connected back everything besides those two harnesses and the coolant lines(need to flush radiator) Any advice is greatly appreciated.

 

As I understand you have VG30E V6 NA, if so check out from page 3 onwards and see where goes each sensor VG30E engine fuel system manual