well first of all, since i installed N20 a few weeks ago i put in a digital fuel pressure gauge from Dynotune (very nice). well today was one of the first days its been like 70* out, lately its been 30-50, and i noticed my fuel pressure when just cruising side rodas at like 30 mph, is below 35. like 34 and sometimes it hit 33. normally th car is around 36-38 when im just cruising, then up around 42 or so when i go WOT. there were no problems with the way the car ran, and WOT pressure was the same but just cruising at low RPMs it was way low. i was wondering why it would do that now, but not a few months ago. possibly because of warm weather?

 

Your fuel pressure regulator has a vacuum line attached to it so that the fuel pressure varies with vacuum. Therefore if you're decelerating, your vacuum increases and your fuel pressure decreases. With the vacuum line removed (simulates WOT condition with zero vacuum) your fuel pressure should be between 41 - 47 psi.