Rojoryu

I posted this in the nitrous section but thought I might get more advice here.

I recently installed a Zex wet kit along with a Zex window switch in my 2000 GT. When the spray starts the window switch will start showing erratic numbers on the display causing the spray to cut in and out. I have gone throught the wiring and tried several coils and injectors to get the rpm signal from but nothing helps. The window switch display will show an accurate rpm reading until it starts spraying nitrous, then it starts wigging out. I have disconnected the window switch and ran the NMU seperately and it ran great. I then hooked the window switch back up and of course, same problems. I dont even have to let it spray to notice the rpms on the window switch display start showing erratic numbers even if you just goose the throttle. Otherwise the display is accurate (at idle and under normal acceleration). I am going to try a new unit hoping the one I have is defective but this seems to be a problem others have encountered but I can't seem to find what the resolution was.