71 Duster 360 turbo build

I’m having a little trouble with my fuel pressure sensor if anyone has a suggestion.

The sensor reads correctly with the engine off(60-80psi), but reads roughly 15% high while driving. The sensor is using the megasquirt sensor ground.
What kind of sensor? Like a generic 0-100psi connected to Generic Inputs? Where is it installed, at the FPR?