944 Won't Run with all 4 injectors connected
 

I've been having an issue with my 87' 944 NA, it won't run with all four fuel injectors plugged in, i can plug in any 3 injectors and it'll work fine but the car dies the second I plug in a fourth one. I have replaced the fuel pump, pressure regulator and damper, injectors, and injector connectors and nothing has changed, I have also replaced the capacitor in the DME and tried two different ROM chips, any help would be appreciated, Thanks!

Time to look at the injector harness for shorts.